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Sample records for inhibitors induce peroxisome

  1. Proteasome inhibitors induce auditory hair cell death through peroxisome dysfunction.

    PubMed

    Lee, Joon No; Kim, Seul-Gi; Lim, Jae-Young; Kim, Se-Jin; Choe, Seong-Kyu; Park, Raekil

    2015-01-01

    Even though bortezomib, a proteasome inhibitor, is a powerful chemotherapeutic agent used to treat multiple myeloma (MM) and other lymphoma cells, recent clinical reports suggest that the proteasome inhibitor therapy may be associated with severe bilateral hearing loss. We herein investigated the adverse effect of proteasome inhibitor on auditory hair cells. Treatment of a proteasome inhibitor destroys stereocilia bundles of hair cells resulting in the disarray of stereocilia in the organ of Corti explants. Since proteasome activity may be potentially important for biogenesis and function of the peroxisome, we tested whether proteasome activity is necessary for maintaining functional peroxisomes. Our results showed that treatment of a proteasome inhibitor significantly decreases both the number of peroxisomes and expression of peroxisomal proteins such as PMP70 and Catalase. In addition, we also found that proteasome inhibitor impairs the import pathway of PTS1-peroxisome matrix proteins. Taken together, our findings support recent clinical reports of hearing loss associated with proteasome inhibition. Mechanistically, peroxisome dysfunction may contribute to hair cell damage and hearing loss in response to the treatment of a proteasome inhibitor.

  2. The membrane peroxin PEX3 induces peroxisome-ubiquitination-linked pexophagy

    PubMed Central

    Yamashita, Shun-ichi; Abe, Kakeru; Tatemichi, Yuki; Fujiki, Yukio

    2014-01-01

    Peroxisomes are degraded by a selective type of autophagy known as pexophagy. Several different types of pexophagy have been reported in mammalian cells. However, the mechanisms underlying how peroxisomes are recognized by autophagy-related machinery remain elusive. PEX3 is a peroxisomal membrane protein (PMP) that functions in the import of PMPs into the peroxisomal membrane and has been shown to interact with pexophagic receptor proteins during pexophagy in yeast. Thus, PEX3 is important not only for peroxisome biogenesis, but also for peroxisome degradation. However, whether PEX3 is involved in the degradation of peroxisomes in mammalian cells is unclear. Here, we report that high levels of PEX3 expression induce pexophagy. In PEX3-loaded cells, peroxisomes are ubiquitinated, clustered, and degraded in lysosomes. Peroxisome targeting of PEX3 is essential for the initial step of this degradation pathway. The degradation of peroxisomes is inhibited by treatment with autophagy inhibitors or siRNA against NBR1, which encodes an autophagic receptor protein. These results indicate that ubiquitin- and NBR1-mediated pexophagy is induced by increased expression of PEX3 in mammalian cells. In addition, another autophagic receptor protein, SQSTM1/p62, is required only for the clustering of peroxisomes. Expression of a PEX3 mutant with substitution of all lysine and cysteine residues by arginine and alanine, respectively, also induces peroxisome ubiquitination and degradation, hence suggesting that ubiquitination of PEX3 is dispensable for pexophagy and an endogenous, unidentified peroxisomal protein is ubiquitinated on the peroxisomal membrane. PMID:25007327

  3. The membrane peroxin PEX3 induces peroxisome-ubiquitination-linked pexophagy.

    PubMed

    Yamashita, Shun-ichi; Abe, Kakeru; Tatemichi, Yuki; Fujiki, Yukio

    2014-09-01

    Peroxisomes are degraded by a selective type of autophagy known as pexophagy. Several different types of pexophagy have been reported in mammalian cells. However, the mechanisms underlying how peroxisomes are recognized by autophagy-related machinery remain elusive. PEX3 is a peroxisomal membrane protein (PMP) that functions in the import of PMPs into the peroxisomal membrane and has been shown to interact with pexophagic receptor proteins during pexophagy in yeast. Thus, PEX3 is important not only for peroxisome biogenesis, but also for peroxisome degradation. However, whether PEX3 is involved in the degradation of peroxisomes in mammalian cells is unclear. Here, we report that high levels of PEX3 expression induce pexophagy. In PEX3-loaded cells, peroxisomes are ubiquitinated, clustered, and degraded in lysosomes. Peroxisome targeting of PEX3 is essential for the initial step of this degradation pathway. The degradation of peroxisomes is inhibited by treatment with autophagy inhibitors or siRNA against NBR1, which encodes an autophagic receptor protein. These results indicate that ubiquitin- and NBR1-mediated pexophagy is induced by increased expression of PEX3 in mammalian cells. In addition, another autophagic receptor protein, SQSTM1/p62, is required only for the clustering of peroxisomes. Expression of a PEX3 mutant with substitution of all lysine and cysteine residues by arginine and alanine, respectively, also induces peroxisome ubiquitination and degradation, hence suggesting that ubiquitination of PEX3 is dispensable for pexophagy and an endogenous, unidentified peroxisomal protein is ubiquitinated on the peroxisomal membrane.

  4. Inhibitors of Growth 1b Suppresses Peroxisome Proliferator-Activated Receptor-β/δ Expression Through Downregulation of Hypoxia-Inducible Factor 1α in Osteoblast Differentiation.

    PubMed

    Qu, Bo; Hong, Zhen; Gong, Kai; Sheng, Jun; Wu, Hong-Hua; Deng, Shao-Lin; Huang, Gang; Ma, Ze-Hui; Pan, Xian-Ming

    2016-04-01

    Bone formation, a highly regulated developmental process, involves osteoblast differentiation, which is controlled by different important transcription factors. Recent evidence has suggested possible negative regulation of inhibitors of growth (ING) 1b on the osteoblast marker expression. The aim of this study is to examine the detailed mechanism by which the activity of ING1b inhibits osteoblast differentiation. In the current study, we investigated the function and mechanism by which ING1b inhibits osteoblast differentiation using C3H10T1/2 mesenchymal stem cells and MC3T3-E1 preosteoblasts. Real-time polymerase chain reaction and Western blotting showed that ING1b was decreased during osteoblast differentiation and ING1b overexpression markedly decreased alkaline phosphatase (ALP) activity, runt-related transcription factor 2 (Runx2) expression, and collagen type 1 synthesis, whereas ING1b silencing significantly upregulated ALP activity, Runx2 expression, and collagen type 1 synthesis. Further studies indicated that ING1b suppressed the expression of peroxisome proliferator-activated receptor (PPAR)-β/δ in a hypoxia-inducible factor (HIF) 1α-dependent manner, while ING1b silencing significantly increased the expression of PPAR-β/δ and HIF1α. Moreover, PPAR-β/δ or HIF1α silencing significantly inhibited ALP activity, Runx2 expression, and collagen type 1 synthesis. These results demonstrated that ING1b is an important regulator of osteoblast differentiation and suppresses PPAR-β/δ. Our study may provide additional insight into osteoblast differentiation and offer a potential new molecular target for osteoporosis. PMID:26849833

  5. NADH Induces the Generation of Superoxide Radicals in Leaf Peroxisomes 1

    PubMed Central

    del Río, Luis A.; Fernández, Víctor M.; Rupérez, Francisco L.; Sandalio, Luisa M.; Palma, José M.

    1989-01-01

    In peroxisomes isolated from pea leaves (Pisum sativum L.) the production of superoxide free radicals (O2−) by xanthine and NADH was investigated. In peroxisomal membranes, 100 micromolar NADH induced the production of O2− radicals. In the soluble fractions of peroxisomes, no generation of O2− radicals was observed by incubation with either NADH or xanthine, although xanthine oxidase was found located predominantly in the matrix of peroxisomes. The failure of xanthine to induce superoxide generation was probably due to the inability to fully suppress the endogenous Mn-superoxide dismutase activity by inhibitors which were inactive against xanthine oxidase. The generation of superoxide radicals in leaf peroxisomes together with the recently described production of these oxygen radicals in glyoxysomes (LM Sandalio, VM Fernández, FL Rupérez, LA del Río [1988] Plant Physiol 87: 1-4) suggests that O2− generation could be a common metabolic property of peroxisomes and further supports the existence of active oxygen-related rôles for peroxisomes in cellular metabolism. PMID:16666612

  6. NADH induces the generation of superoxide radicals in leaf peroxisomes. [Pisum sativum L

    SciTech Connect

    del Rio, L.A.; Sandalio, L.M.; Palma, J.M. ); Fernandez, V.M.; Ruperez, F.L. )

    1989-03-01

    In peroxisomes isolated from pea leaves (Pisum sativum L.) the production of superoxide free radicals (O{sub 2}{sup {minus}}) by xanthine and NADH was investigated. In peroxisomal membranes, 100 micromolar NADH induced the production of O{sub 2}{sup {minus}} radicals. In the soluble fractions of peroxisomes, no generation of O{sub 2}{sup {minus}} radicals was observed by incubation with either NADH or xanthine, although xanthine oxidase was found located predominantly in the matrix of peroxisomes. The failure of xanthine to induce superoxide generation was probably due to the inability to fully suppress the endogenous Mn-superoxide dismutase activity by inhibitors which were inactive against xanthine oxidase. The generation of superoxide radicals in leaf peroxisomes together with the recently described production of these oxygen radicals in glyoxysomes suggests that O{sub 2}{sup {minus}} generation could be a common metabolic property of peroxisomes and further supports the existence of active oxygen-related roles for peroxisomes in cellular metabolism.

  7. Biosynthesis of the peroxisomal dihydroxyacetone synthase from Hansenula polymorpha in Saccharomyces cerevisiae induces growth but not proliferation of peroxisomes.

    PubMed

    Gödecke, A; Veenhuis, M; Roggenkamp, R; Janowicz, Z A; Hollenberg, C P

    1989-07-01

    The DAS gene of Hansenula polymorpha was expressed in Saccharomyces cerevisiae under the control of different promoters. The heterologously synthesized dihydroxyacetone synthase (DHAS), a peroxisomal enzyme in H. polymorpha, shows enzymatic activity in baker's yeast. The enzyme was imported into the peroxisomes of S. cerevisiae not only under the appropriate physiological conditions for peroxisome proliferation (oleic acid media), but also in glucose-grown cells where it induced the enlargement of the few peroxisomes present. This growth process was not accompanied by an increase in the number of microbodies, which suggests a separate control mechanism for peroxisomal proliferation.

  8. Peroxisome proliferator-activated receptor γ agonist efatutazone impairs transforming growth factor β2-induced motility of epidermal growth factor receptor tyrosine kinase inhibitor-resistant lung cancer cells.

    PubMed

    Serizawa, Masakuni; Murakami, Haruyasu; Watanabe, Masaru; Takahashi, Toshiaki; Yamamoto, Nobuyuki; Koh, Yasuhiro

    2014-06-01

    Epidermal growth factor receptor-tyrosine kinase inhibitors (EGFR-TKI) are effective for non-small cell lung cancers (NSCLC) with EGFR-activating mutations. However, most responders develop resistance. Efatutazone, a novel peroxisome proliferator-activated receptor gamma (PPARγ) agonist, is currently under clinical evaluation; it has antiproliferative effects and induces cellular morphological changes and differentiation. The present study investigated the effects of efatutazone in EGFR-TKI-resistant NSCLC cells, while focusing on cell motility. The PC-9-derived NSCLC cell lines PC-9ER and PC-9ZD, resistant to EGFR-TKI due to v-crk avian sarcoma virus CT10 oncogene homolog-like (CRKL) amplification-induced phosphatidylinositol 3-kinase (PI3K)/v-akt murine thymoma viral oncogene homolog (AKT) activation and an EGFR T790M mutation, respectively, were used. These cells exhibit enhanced cell motility due to transforming growth factor β (TGF-β)/Smad2 family member 2 (Smad2) pathway activation. Efatutazone had no growth-inhibitory effect on the tested cells but inhibited the motility of EGFR-TKI-resistant cells in wound closure and transwell assays. Efatutazone plus erlotinib treatment provided greater inhibition of PC-9ER cell migration than efatutazone or erlotinib alone. Efatutazone suppressed increased TGF-β2 secretion from both cell lines (shown by ELISA) and downregulation of TGF-β2 transcription (observed by quantitative RT-PCR). Immunoblot analysis and luciferase assays revealed that efatutazone suppressed Smad2 phosphorylation and its transcriptional activity. These results suggest that efatutazone inhibits cell motility by antagonizing the TGF-β/Smad2 pathway and effectively prevents metastasis in NSCLC patients with acquired resistance to EGFR-TKI regardless of the resistance mechanism.

  9. ATM functions at the peroxisome to induce pexophagy in response to ROS.

    PubMed

    Zhang, Jiangwei; Tripathi, Durga Nand; Jing, Ji; Alexander, Angela; Kim, Jinhee; Powell, Reid T; Dere, Ruhee; Tait-Mulder, Jacqueline; Lee, Ji-Hoon; Paull, Tanya T; Pandita, Raj K; Charaka, Vijaya K; Pandita, Tej K; Kastan, Michael B; Walker, Cheryl Lyn

    2015-10-01

    Peroxisomes are highly metabolic, autonomously replicating organelles that generate reactive oxygen species (ROS) as a by-product of fatty acid β-oxidation. Consequently, cells must maintain peroxisome homeostasis, or risk pathologies associated with too few peroxisomes, such as peroxisome biogenesis disorders, or too many peroxisomes, inducing oxidative damage and promoting diseases such as cancer. We report that the PEX5 peroxisome import receptor binds ataxia-telangiectasia mutated (ATM) and localizes this kinase to the peroxisome. In response to ROS, ATM signalling activates ULK1 and inhibits mTORC1 to induce autophagy. Specificity for autophagy of peroxisomes (pexophagy) is provided by ATM phosphorylation of PEX5 at Ser 141, which promotes PEX5 monoubiquitylation at Lys 209, and recognition of ubiquitylated PEX5 by the autophagy adaptor protein p62, directing the autophagosome to peroxisomes to induce pexophagy. These data reveal an important new role for ATM in metabolism as a sensor of ROS that regulates pexophagy.

  10. Peroxisomal Biogenesis in Ischemic Brain

    PubMed Central

    Young, Jennifer M.; Nelson, Jonathan W.; Cheng, Jian; Zhang, Wenri; Mader, Sarah; Davis, Catherine M.; Morrison, Richard S.

    2015-01-01

    Abstract Aims: Peroxisomes are highly adaptable and dynamic organelles, adjusting their size, number, and enzyme composition to changing environmental and metabolic demands. We determined whether peroxisomes respond to ischemia, and whether peroxisomal biogenesis is an adaptive response to cerebral ischemia. Results: Focal cerebral ischemia induced peroxisomal biogenesis in peri-infarct neurons, which was associated with a corresponding increase in peroxisomal antioxidant enzyme catalase. Peroxisomal biogenesis was also observed in primary cultured cortical neurons subjected to ischemic insult induced by oxygen-glucose deprivation (OGD). A catalase inhibitor increased OGD-induced neuronal death. Moreover, preventing peroxisomal proliferation by knocking down dynamin-related protein 1 (Drp1) exacerbated neuronal death induced by OGD, whereas enhancing peroxisomal biogenesis pharmacologically using a peroxisome proliferator-activated receptor-alpha agonist protected against neuronal death induced by OGD. Innovation: This is the first documentation of ischemia-induced peroxisomal biogenesis in mammalian brain using a combined in vivo and in vitro approach, electron microscopy, high-resolution laser-scanning confocal microscopy, and super-resolution structured illumination microscopy. Conclusion: Our findings suggest that neurons respond to ischemic injury by increasing peroxisome biogenesis, which serves a protective function, likely mediated by enhanced antioxidant capacity of neurons. Antioxid. Redox Signal. 22, 109–120. PMID:25226217

  11. The p33 auxiliary replicase protein of Cucumber necrosis virus targets peroxisomes and infection induces de novo peroxisome formation from the endoplasmic reticulum.

    PubMed

    Rochon, D'Ann; Singh, Bhavana; Reade, Ron; Theilmann, Jane; Ghoshal, Kankana; Alam, Syed Benazir; Maghodia, Ajay

    2014-03-01

    Tombusviruses replicate on pre-existing organelles such as peroxisomes or mitochondria, the membranes of which become extensively reorganized into multivesicular bodies (MVBs) during the infection process. Cucumber necrosis virus (CNV) has previously been shown to replicate in association with peroxisomes in yeast. We show that CNV induces MVBs from peroxisomes in infected plants and that GFP-tagged p33 auxiliary replicase protein colocalizes with YFP(SKL), a peroxisomal marker. Most remarkably, the ER of CNV infected Nicotiana benthamiana 16C plants undergoes a dramatic reorganization producing numerous new peroxisome-like structures that associate with CNV p33, thus likely serving as a new site for viral RNA replication. We also show that plants agroinfiltrated with p33 develop CNV-like necrotic symptoms which are associated with increased levels of peroxide. Since peroxisomes are a site for peroxide catabolism, and peroxide is known to induce plant defense responses, we suggest that dysfunctional peroxisomes contribute to CNV induced necrosis.

  12. Expression level of methanol-inducible peroxisomal proteins and peroxisome morphology are affected by oxygen conditions and mitochondrial respiratory pathway function in the methylotrophic yeast Candida boidinii.

    PubMed

    Fujimura, Shuki; Yurimoto, Hiroya; Kurimoto, Shota; Matsufuji, Yoshimi; Ito, Takashi; Hayakawa, Takashi; Tomizuka, Noboru; Sakai, Yasuyoshi; Nakagawa, Tomoyuki

    2013-06-01

    In the methylotrophic yeast, Candida boidinii, methanol-inducible peroxisomal proteins, for example alcohol oxidase (AOD), dihydroxyacetone synthase (DAS), and peroxisomal glutathione peroxidase (Pmp20), were induced only under aerobic conditions, while expression of PMP47 encoding peroxisomal integral membrane protein Pmp47 was independent of oxygen conditions. Expression of the methanol-inducible peroxisomal enzymes was repressed by inhibition of the mitochondrial respiratory chain. In the respiratory-deficient (ρ0) mutant strain, their induction was at very low levels despite the presence of oxygen, whereas the expression of PMP47 was unaffected. Taken together, these facts indicate that C. boidinii can sense oxygen conditions, and that mitochondrial respiratory function may have a profound effect on induction of methanol-inducible gene expression of peroxisomal proteins. Peroxisome morphology was also affected by oxygen conditions and respiratory function. Under hypoxic conditions or respiration-inhibited conditions, cells induced by methanol contained small peroxisomes, indicating that peroxisome biogenesis and the protein import machinery were not affected by oxygen conditions but that peroxisome morphology was dependent on induction of peroxisomal matrix proteins.

  13. ATM Functions at the Peroxisome to Induce Pexophagy in Response to ROS

    PubMed Central

    Alexander, Angela; Kim, Jinhee; Powell, Reid T.; Dere, Ruhee; Tait-Mulder, Jacqueline; Lee, Ji-Hoon; Paull, Tanya T.; Pandita, Raj K.; Charaka, Vijaya K.; Pandita, Tej K.; Kastan, Michael B.; Walker, Cheryl Lyn

    2015-01-01

    Peroxisomes are highly metabolic, autonomously replicating organelles that generate ROS as a by product of fatty acid β-oxidation. Consequently, cells must maintain peroxisome homeostasis, or risk pathologies associated with too few peroxisomes, such as peroxisome biogenesis disorders, or too many peroxisomes, inducing oxidative damage and promoting diseases such as cancer. We report that the PEX5 peroxisome import receptor binds ataxia-telangiectasia mutated (ATM) and localizes this kinase to the peroxisome. In response to reactive oxygen species (ROS), ATM signaling activates ULK1 and inhibits mTORC1 to induce autophagy. Specificity for autophagy of peroxisomes (pexophagy) is provided by ATM phosphorylation of PEX5 at Ser141, which promotes PEX5 mono-ubiquitination at K209, and recognition of ubiquitinated PEX5 by the autophagy adapter protein p62, directing the autophagosome to peroxisomes to induce pexophagy. These data reveal an important new role for ATM in metabolism as a sensor of ROS that regulates pexophagy. PMID:26344566

  14. Plant peroxisomes are degraded by starvation-induced and constitutive autophagy in tobacco BY-2 suspension-cultured cells

    PubMed Central

    Voitsekhovskaja, Olga V.; Schiermeyer, Andreas; Reumann, Sigrun

    2014-01-01

    Very recently, autophagy has been recognized as an important degradation pathway for quality control of peroxisomes in Arabidopsis plants. To further characterize the role of autophagy in plant peroxisome degradation, we generated stable transgenic suspension-cultured cell lines of heterotrophic Nicotiana tabacum L. cv. Bright Yellow 2 expressing a peroxisome-targeted version of enhanced yellow fluorescent protein. Indeed, this cell line model system proved advantageous for detailed cytological analyses of autophagy stages and for quantification of cellular peroxisome pools under different culturing conditions and upon inhibitor applications. Complementary biochemical, cytological, and pharmacological analyses provided convincing evidence for peroxisome degradation by bulk autophagy during carbohydrate starvation. This degradation was slowed down by the inhibitor of autophagy, 3-methyladenine (3-MA), but the 3-MA effect ceased at advanced stages of starvation, indicating that another degradation mechanism for peroxisomes might have taken over. 3-MA also caused an increase particularly in peroxisomal proteins and cellular peroxisome numbers when applied under nutrient-rich conditions in the logarithmic growth phase, suggesting a high turnover rate for peroxisomes by basal autophagy under non-stress conditions. Together, our data demonstrate that a great fraction of the peroxisome pool is subject to extensive autophagy-mediated turnover under both nutrient starvation and optimal growth conditions. Our analyses of the cellular pool size of peroxisomes provide a new tool for quantitative investigations of the role of plant peroxisomes in reactive oxygen species metabolism. PMID:25477890

  15. PPARα Activation Induces Nε-Lys-Acetylation of Rat Liver Peroxisomal Multifunctional Enzyme Type 1

    PubMed Central

    Contreras, Miguel A.; Alzate, Oscar; Singh, Avtar K.

    2013-01-01

    Peroxisomes are ubiquitous subcellular organelles that participate in metabolic and disease processes, with few of its proteins undergoing posttranslational modifications. As the role of lysine-acetylation has expanded into the cellular intermediary metabolism, we used a combination of differential centrifugation, organelle isolation by linear density gradient centrifugation, western blot analysis, and peptide fingerprinting and amino acid sequencing by mass spectrometry to investigate protein acetylation in control and ciprofibrate-treated rat liver peroxisomes. Organelle protein samples isolated by density gradient centrifugation from PPARα-agonist treated rat liver screened with an anti-Nε-acetyl lysine antibody revealed a single protein band of 75 kDa. Immunoprecipitation with this antibody resulted in the precipitation of a protein from the protein pool of ciprofibrate-induced peroxisomes, but not from the protein pool of non-induced peroxisomes. Peptide mass fingerprinting analysis identified the protein as the peroxisomal multifunctional enzyme type 1. In addition, mass spectrometry-based amino acid sequencing resulted in the identification of unique peptides containing 4 acetylated-Lys residues (K155, K173, K190, and K583). This is the first report that demonstrates posttranslational acetylation of a peroxisomal enzyme in PPARα-dependent proliferation of peroxisomes in rat liver. PMID:24092543

  16. Peroxisome proliferator-activated receptorα agonists differentially regulate inhibitor of DNA binding expression in rodents and human cells.

    PubMed

    González, María Del Carmen; Corton, J Christopher; Acero, Nuria; Muñoz-Mingarro, Dolores; Quirós, Yolanda; Alvarez-Millán, Juan José; Herrera, Emilio; Bocos, Carlos

    2012-01-01

    Inhibitor of DNA binding (Id2) is a helix-loop-helix (HLH) transcription factor that participates in cell differentiation and proliferation. Id2 has been linked to the development of cardiovascular diseases since thiazolidinediones, antidiabetic agents and peroxisome proliferator-activated receptor (PPAR) gamma agonists, have been reported to diminish Id2 expression in human cells. We hypothesized that PPARα activators may also alter Id2 expression. Fenofibrate diminished hepatic Id2 expression in both late pregnant and unmated rats. In 24 hour fasted rats, Id2 expression was decreased under conditions known to activate PPARα. In order to determine whether the fibrate effects were mediated by PPARα, wild-type mice and PPARα-null mice were treated with Wy-14,643 (WY). WY reduced Id2 expression in wild-type mice without an effect in PPARα-null mice. In contrast, fenofibrate induced Id2 expression after 24 hours of treatment in human hepatocarcinoma cells (HepG2). MK-886, a PPARα antagonist, did not block fenofibrate-induced activation of Id2 expression, suggesting a PPARα-independent effect was involved. These findings confirm that Id2 is a gene responsive to PPARα agonists. Like other genes (apolipoprotein A-I, apolipoprotein A-V), the opposite directional transcriptional effect in rodents and a human cell line further emphasizes that PPARα agonists have different effects in rodents and humans.

  17. Peroxisome Proliferator-Activated Receptorα Agonists Differentially Regulate Inhibitor of DNA Binding Expression in Rodents and Human Cells

    PubMed Central

    González, María del Carmen; Corton, J. Christopher; Acero, Nuria; Muñoz-Mingarro, Dolores; Quirós, Yolanda; Álvarez-Millán, Juan José; Herrera, Emilio; Bocos, Carlos

    2012-01-01

    Inhibitor of DNA binding (Id2) is a helix-loop-helix (HLH) transcription factor that participates in cell differentiation and proliferation. Id2 has been linked to the development of cardiovascular diseases since thiazolidinediones, antidiabetic agents and peroxisome proliferator-activated receptor (PPAR) gamma agonists, have been reported to diminish Id2 expression in human cells. We hypothesized that PPARα activators may also alter Id2 expression. Fenofibrate diminished hepatic Id2 expression in both late pregnant and unmated rats. In 24 hour fasted rats, Id2 expression was decreased under conditions known to activate PPARα. In order to determine whether the fibrate effects were mediated by PPARα, wild-type mice and PPARα-null mice were treated with Wy-14,643 (WY). WY reduced Id2 expression in wild-type mice without an effect in PPARα-null mice. In contrast, fenofibrate induced Id2 expression after 24 hours of treatment in human hepatocarcinoma cells (HepG2). MK-886, a PPARα antagonist, did not block fenofibrate-induced activation of Id2 expression, suggesting a PPARα-independent effect was involved. These findings confirm that Id2 is a gene responsive to PPARα agonists. Like other genes (apolipoprotein A-I, apolipoprotein A-V), the opposite directional transcriptional effect in rodents and a human cell line further emphasizes that PPARα agonists have different effects in rodents and humans. PMID:22701468

  18. Molecular basis of non-responsiveness to peroxisome proliferators: the guinea-pig PPARalpha is functional and mediates peroxisome proliferator-induced hypolipidaemia.

    PubMed Central

    Bell, A R; Savory, R; Horley, N J; Choudhury, A I; Dickins, M; Gray, T J; Salter, A M; Bell, D R

    1998-01-01

    The guinea pig does not undergo peroxisome proliferation in response to peroxisome proliferators, in contrast with other rodents. To understand the molecular basis of this phenotype, the peroxisome proliferator activated receptor alpha (PPARalpha) from guinea-pig liver was cloned; it encodes a protein of 467 amino acid residues that is similar to rodent and human PPARalpha. The guinea-pig PPARalpha showed a high substitution rate: maximum likelihood analysis was consistent with rodent monophyly, but could not exclude rodent polyphyly (P approximately 0.06). The guinea-pig PPARalpha cDNA was expressed in 293 cells and mediated the induction of the luciferase reporter gene by the peroxisome proliferator, Wy-14,643, dependent on the presence of a peroxisome proliferator response element. Moreover the PPARalpha RNA and protein were expressed in guinea-pig liver, although at lower levels than in a species which is responsive to peroxisome proliferators, the mouse. To determine whether the guinea-pig PPARalpha mediated any physiological effects, guinea pigs were exposed to two selective PPARalpha agonists, Wy-14, 643 and methylclofenapate; both compounds induced hypolipidaemia. Thus the guinea pig is a useful model for human responses to peroxisome proliferators. PMID:9620871

  19. Identification and Characterization of a Stress-Inducible and a Constitutive Small Heat-Shock Protein Targeted to the Matrix of Plant Peroxisomes1[W

    PubMed Central

    Ma, Changle; Haslbeck, Martin; Babujee, Lavanya; Jahn, Olaf; Reumann, Sigrun

    2006-01-01

    Small heat-shock proteins (sHsps) are widespread molecular chaperones for which a peroxisomal localization has not yet been reported. The Arabidopsis (Arabidopsis thaliana) genome encodes two sHsps with putative peroxisomal targeting signals type 1 or 2 (PTS1 or PTS2). As demonstrated by double-labeling experiments using full-length fusion proteins with enhanced yellow fluorescent protein and deletion constructs lacking the putative targeting domains, AtHsp15.7 (At5g37670) and AtAcd31.2 (At1g06460) are targeted to the peroxisome matrix by a functional PTS1 (SKL>) and a functional PTS2 (RLx5HF), respectively. The peroxisomal localization of AtAcd31.2 was further confirmed by isolation of leaf peroxisomes from Arabidopsis by two successive sucrose density gradients, protein separation by one- and two-dimensional gel electrophoresis, and mass spectrometric protein identification. When AtHsp15.7 and AtAcd31.2 were heterologously expressed in yeast (Saccharomyces cerevisiae) and directed to the cytosol by deletion of the PTSs, both sHsps were able to complement the morphological phenotype of yeast mutants deficient in the cytosolic homologs ScHsp42 or ScHsp26. According to expression studies by reverse transcription-PCR, AtAcd31.2 is constitutively expressed, whereas AtHsp15.7 is hardly expressed under normal conditions but strongly induced by heat and oxidative stress, the latter of which was triggered by the catalase inhibitor 3-aminotriazole or the herbicide methyl viologen applied by watering of whole plants or infiltration of rosette leaves. Thus, plants are exceptional among eukaryotes in employing sHsps in the peroxisome matrix to prevent unspecific aggregation of partially denatured proteins under both physiological and stress conditions. PMID:16531488

  20. Compromised peroxisomes in idiopathic pulmonary fibrosis, a vicious cycle inducing a higher fibrotic response via TGF-β signaling.

    PubMed

    Oruqaj, Gani; Karnati, Srikanth; Vijayan, Vijith; Kotarkonda, Lakshmi Kanth; Boateng, Eistine; Zhang, Wenming; Ruppert, Clemens; Günther, Andreas; Shi, Wei; Baumgart-Vogt, Eveline

    2015-04-21

    Idiopathic pulmonary fibrosis (IPF) is a devastating disease, and its pathogenic mechanisms remain incompletely understood. Peroxisomes are known to be important in ROS and proinflammatory lipid degradation, and their deficiency induces liver fibrosis. However, altered peroxisome functions in IPF pathogenesis have never been investigated. By comparing peroxisome-related protein and gene expression in lung tissue and isolated lung fibroblasts between human control and IPF patients, we found that IPF lungs exhibited a significant down-regulation of peroxisomal biogenesis and metabolism (e.g., PEX13p and acyl-CoA oxidase 1). Moreover, in vivo the bleomycin-induced down-regulation of peroxisomes was abrogated in transforming growth factor beta (TGF-β) receptor II knockout mice indicating a role for TGF-β signaling in the regulation of peroxisomes. Furthermore, in vitro treatment of IPF fibroblasts with the profibrotic factors TGF-β1 or tumor necrosis factor alpha (TNF-α) was found to down-regulate peroxisomes via the AP-1 signaling pathway. Therefore, the molecular mechanisms by which reduced peroxisomal functions contribute to enhanced fibrosis were further studied. Direct down-regulation of PEX13 by RNAi induced the activation of Smad-dependent TGF-β signaling accompanied by increased ROS production and resulted in the release of cytokines (e.g., IL-6, TGF-β) and excessive production of collagen I and III. In contrast, treatment of fibroblasts with ciprofibrate or WY14643, PPAR-α activators, led to peroxisome proliferation and reduced the TGF-β-induced myofibroblast differentiation and collagen protein in IPF cells. Taken together, our findings suggest that compromised peroxisome activity might play an important role in the molecular pathogenesis of IPF and fibrosis progression, possibly by exacerbating pulmonary inflammation and intensifying the fibrotic response in the patients.

  1. Peroxisomes and Kidney Injury

    PubMed Central

    2016-01-01

    Abstract Significance: Peroxisomes are organelles present in most eukaryotic cells. The organs with the highest density of peroxisomes are the liver and kidneys. Peroxisomes possess more than fifty enzymes and fulfill a multitude of biological tasks. They actively participate in apoptosis, innate immunity, and inflammation. In recent years, a considerable amount of evidence has been collected to support the involvement of peroxisomes in the pathogenesis of kidney injury. Recent Advances: The nature of the two most important peroxisomal tasks, beta-oxidation of fatty acids and hydrogen peroxide turnover, functionally relates peroxisomes to mitochondria. Further support for their communication and cooperation is furnished by the evidence that both organelles share the components of their division machinery. Until recently, the majority of studies on the molecular mechanisms of kidney injury focused primarily on mitochondria and neglected peroxisomes. Critical Issues: The aim of this concise review is to introduce the reader to the field of peroxisome biology and to provide an overview of the evidence about the contribution of peroxisomes to the development and progression of kidney injury. The topics of renal ischemia–reperfusion injury, endotoxin-induced kidney injury, diabetic nephropathy, and tubulointerstitial fibrosis, as well as the potential therapeutic implications of peroxisome activation, are addressed in this review. Future Directions: Despite recent progress, further studies are needed to elucidate the molecular mechanisms induced by dysfunctional peroxisomes and the role of the dysregulated mitochondria–peroxisome axis in the pathogenesis of renal injury. Antioxid. Redox Signal. 25, 217–231. PMID:26972522

  2. Gene expression for peroxisome-associated enzymes in hepatocellular carcinomas induced by ciprofibrate, a hypolipidemic compound

    SciTech Connect

    Rao, M.S.; Nemali, M.R.; Reddy, J.K.

    1986-03-05

    Administration of hypolipidemic compounds leads to marked proliferation of peroxisomes and peroxisome-associated enzymes (PAE) in the livers of rodents and non-rodent species. The increase peroxisome-associated enzymes such as fatty acid ..beta..-oxidation system and catalase is shown to be due to an increase in the levels of mRNA. In this experiment they have examined hepatocellular carcinomas (HCC), induced in male F-344 rats by ciprofibrate (0.025%, w/w for 60 weeks), for gene expression of PAE. Total RNA was purified from HCC as well as from control and ciprofibrate (0.025% for 2 weeks) fed rat livers. Northern blot analysis was performed using (32/sub p/)cDNA probes for albumin, fatty acetyl-CoA oxidase, enoyl-CoA hydratase 3-hydroxyacyl-CoA dehydrogenase bifunctional enzyme and catalase. mRNA levels in HCC for albumin, fatty acid ..beta..-oxidation enzymes and catalase were comparable with those levels observed in the livers of rats given ciprofibrate for 2 weeks. In control livers the mRNAs for ..beta..-oxidation enzymes were low. Albumin mRNA levels in all the 3 groups were comparable. Additional studies are necessary to determine whether the increased level of mRNAs for the ..beta..-oxidation enzymes in HCC is due to the effect of ciprofibrate or to the gene amplification.

  3. Peroxisome proliferator-activated receptor {alpha} agonist-induced down-regulation of hepatic glucocorticoid receptor expression in SD rats

    SciTech Connect

    Chen Xiang; Li Ming; Sun Weiping; Bi Yan; Cai Mengyin; Liang Hua; Yu Qiuqiong; He Xiaoying; Weng Jianping

    2008-04-18

    It was reported that glucocorticoid production was inhibited by fenofibrate through suppression of type-1 11{beta}-hydroxysteroid dehydrogenase gene expression in liver. The inhibition might be a negative-feedback regulation of glucocorticoid receptor (GR) activity by peroxisome proliferator-activated receptor alpha (PPAR{alpha}), which is quickly induced by glucocorticoid in the liver. However, it is not clear if GR expression is changed by fenofibrate-induced PPAR{alpha} activation. In this study, we tested this possibility in the liver of Sprague-Dawley rats. GR expression was reduced by fenofibrate in a time- and does-dependent manner. The inhibition was observed in liver, but not in fat and muscle. The corticosterone level in the blood was increased significantly by fenofibrate. These effects of fenofibrate were abolished by PPAR{alpha} inhibitor MK886, suggesting that fenofibrate activated through PPAR{alpha}. In conclusion, inhibition of GR expression may represent a new molecular mechanism for the negative feedback regulation of GR activity by PPAR{alpha}.

  4. Protective Role for Tissue Inhibitor of Metalloproteinase-4, a Novel Peroxisome Proliferator-Activated Receptor-γ Target Gene, in Smooth Muscle in Deoxycorticosterone Acetate-Salt Hypertension.

    PubMed

    Ketsawatsomkron, Pimonrat; Keen, Henry L; Davis, Deborah R; Lu, Ko-Ting; Stump, Madeliene; De Silva, T Michael; Hilzendeger, Aline M; Grobe, Justin L; Faraci, Frank M; Sigmund, Curt D

    2016-01-01

    Loss of peroxisome proliferator-activated receptor-γ (PPARγ) function causes hypertension, whereas its activation lowers blood pressure. Evidence suggests that these effects may be attributable to PPARγ activity in the vasculature. However, the specific transcriptional targets of PPARγ in vessels remain largely unidentified. In this study, we examined the role of smooth muscle PPARγ during salt-sensitive hypertension and investigated its transcriptional targets and functional effect. Transgenic mice expressing dominant-negative PPARγ (S-P467L) in smooth muscle cells were more prone to deoxycorticosterone acetate-salt-induced hypertension and mesenteric arterial dysfunction compared with nontransgenic controls. Despite similar morphometry at baseline, vascular remodeling in conduit and small arteries was enhanced in S-P467L after deoxycorticosterone acetate-salt treatment. Gene expression profiling in aorta and mesenteric arteries revealed significantly decreased expression of tissue inhibitor of metalloproteinase-4 (TIMP-4) in S-P467L. Expression of TIMP-4 was increased by deoxycorticosterone acetate-salt treatment, but this increase was ablated in S-P467L. Interference with PPARγ activity either by treatment with a PPARγ inhibitor, GW9662, or by expressing P467L PPARγ markedly suppressed TIMP-4 in primary smooth muscle cells. PPARγ binds to a PPAR response element (PPRE) in chromatin close to the TIMP-4 gene in smooth muscle cells, suggesting that TIMP-4 is a novel target of PPARγ. The interference with PPARγ and decrease in TIMP-4 were accompanied by an increase in total matrix metalloproteinase activity. PPARγ-mediated loss of TIMP-4 increased, whereas overexpression of TIMP-4 decreased smooth muscle cell migration in a scratch assay. Our findings highlight a protective mechanism induced by PPARγ in deoxycorticosterone acetate-salt treatment, establishing a novel mechanistic link between PPARγ and TIMP-4.

  5. Histone Deacetylase Inhibitor Upregulates Peroxisomal Fatty Acid Oxidation and Inhibits Apoptotic Cell Death in Abcd1-Deficient Glial Cells

    PubMed Central

    Singh, Jaspreet; Khan, Mushfiquddin; Pujol, Aurora; Baarine, Mauhamad; Singh, Inderjit

    2013-01-01

    In X-ALD, mutation/deletion of ALD gene (ABCD1) and the resultant very long chain fatty acid (VLCFA) derangement has dramatically opposing effects in astrocytes and oligodendrocytes. While loss of Abcd1 in astrocytes produces a robust inflammatory response, the oligodendrocytes undergo cell death leading to demyelination in X-linked adrenoleukodystrophy (X-ALD). The mechanisms of these distinct pathways in the two cell types are not well understood. Here, we investigated the effects of Abcd1-knockdown and the subsequent alteration in VLCFA metabolism in human U87 astrocytes and rat B12 oligodendrocytes. Loss of Abcd1 inhibited peroxisomal β-oxidation activity and increased expression of VLCFA synthesizing enzymes, elongase of very long chain fatty acids (ELOVLs) (1 and 3) in both cell types. However, higher induction of ELOVL's in Abcd1-deficient B12 oligodendrocytes than astrocytes suggests that ELOVL pathway may play a prominent role in oligodendrocytes in X-ALD. While astrocytes are able to maintain the cellular homeostasis of anti-apoptotic proteins, Abcd1-deletion in B12 oligodendrocytes downregulated the anti-apototic (Bcl-2 and Bcl-xL) and cell survival (phospho-Erk1/2) proteins, and upregulated the pro-apoptotic proteins (Bad, Bim, Bax and Bid) leading to cell loss. These observations provide insights into different cellular signaling mechanisms in response to Abcd1-deletion in two different cell types of CNS. The apoptotic responses were accompanied by activation of caspase-3 and caspase-9 suggesting the involvement of mitochondrial-caspase-9-dependent mechanism in Abcd1-deficient oligodendrocytes. Treatment with histone deacetylase (HDAC) inhibitor suberoylanilide hydroxamic acid (SAHA) corrected the VLCFA derangement both in vitro and in vivo, and inhibited the oligodendrocytes loss. These observations provide a proof-of principle that HDAC inhibitor SAHA may have a therapeutic potential for X-ALD. PMID:23923017

  6. Peroxisome proliferator-activated receptor gamma ligands induce growth inhibition and apoptosis of human B lymphocytic leukemia.

    PubMed

    Zang, Chuanbing; Liu, Hongyu; Posch, Maximilian G; Waechter, Maries; Facklam, Margit; Fenner, Martin H; Ruthardt, Martin; Possinger, Kurt; Phillip Koeffler, H; Elstner, Elena

    2004-04-01

    This study examined the expression and structural intactness of peroxisome proliferator-activated receptor gamma (PPARgamma) in human acute lymphocytic leukemia (ALL) cells and determined the effect of PPARgamma ligands on growth and apoptosis of these cells. We noted that all lymphocytic leukemia cell lines expressed PPARgamma and no PPARgamma mutations were found in these cell lines as indicated by SSCP analysis. Effect of the PPARgamma ligands on the proliferation, differentiation and apoptosis of B type ALL cells was further examined. Treatment of these cells with the PPARgamma ligands Pioglitazone (PGZ) and 15-deoxy-delta (12,14)-prostaglandin J2 (15d-PGJ2) resulted in growth inhibition in a dose-dependent manner which was associated with a G1 to S cell cycle arrest. However, this effect appeared to be PPARgamma-independent since several PPARgamma antagonists could not reverse this effect. No differentiation was induced by this treatment. Four out of five cell lines underwent apoptosis after culture with the PPARgamma ligands. This effect was partially caspase-dependent because a pan-caspase inhibitor partially reversed this effect. In conclusion, our results suggest that PPARgamma ligands may offer a new therapeutic approach to aid in the treatment of ALL. PMID:15109539

  7. Chemical synthesis, docking studies and biological effects of a pan peroxisome proliferator-activated receptor agonist and cyclooxygenase inhibitor.

    PubMed

    Santin, José Roberto; Uchôa, Flávia D T; Lima, Maria do Carmo A; Rabello, Marcelo M; Machado, Isabel Daufenback; Hernandes, Marcelo Z; Amato, Angelica A; Milton, Flora Aparecida; Webb, Paul; Neves, Francisco de Assis Rocha; Galdino, Suely L; Pitta, Ivan Rocha; Farsky, Sandra H P

    2013-03-12

    The compound (5Z)-5-[(5-bromo-1H-indol-3-yl)methylene]-3-(4-chlorobenzyl)-thiazolidine-2,4-dione (LYSO-7) was synthesised in order to obtain a new type of anti-inflammatory drug, designed with hybrid features to inhibit cyclooxygenase (COX) and also to activate peroxisome proliferator-activated receptor (PPAR). Results obtained from docking (in silico) studies corroborated with experimental data, showing the potential affinity between the studied ligand and targets. The specificity of LYSO-7 for COX-enzymes was detected by the inhibition of COX-1 and COX-2 activities by 30% and 20%, respectively. In transactivation reporter gene assays LYSO-07 showed a pan partial agonist effect on the three PPAR subtypes (PPARγ, PPARα and PPARβ/δ). The agonist action on PPARγ was also observed by a pharmacological approach, as the reduction in the Escherichia coli lipopolysaccharide (LPS)-induced interleukin 1 beta (IL-1β) secretion and nitric oxide (NO) production by mouse neutrophils was blocked by GW9962, a specific PPARγ antagonist. Additionally, the in vivo effect was measured by reduced carrageenan-induced neutrophil influx into the subcutaneous tissue of mice. Taken together, these data show that LYSO-7 displays a potent in vivo anti-inflammatory effect during the innate acute response, which is dependent on its associated COX inhibitory activities and PPAR activation. PMID:23305993

  8. Brain peroxisomes.

    PubMed

    Trompier, D; Vejux, A; Zarrouk, A; Gondcaille, C; Geillon, F; Nury, T; Savary, S; Lizard, G

    2014-03-01

    Peroxisomes are essential organelles in higher eukaryotes as they play a major role in numerous metabolic pathways and redox homeostasis. Some peroxisomal abnormalities, which are often not compatible with life or normal development, were identified in severe demyelinating and neurodegenerative brain diseases. The metabolic roles of peroxisomes, especially in the brain, are described and human brain peroxisomal disorders resulting from a peroxisome biogenesis or a single peroxisomal enzyme defect are listed. The brain abnormalities encountered in these disorders (demyelination, oxidative stress, inflammation, cell death, neuronal migration, differentiation) are described and their pathogenesis are discussed. Finally, the contribution of peroxisomal dysfunctions to the alterations of brain functions during aging and to the development of Alzheimer's disease is considered.

  9. Fenofibrate, a peroxisome proliferator-activated receptor α ligand, prevents abnormal liver function induced by a fasting–refeeding process

    SciTech Connect

    Lee, Joon No; Dutta, Raghbendra Kumar; Kim, Seul-Gi; Lim, Jae-Young; Kim, Se-Jin; Choe, Seong-Kyu; Yoo, Kyeong-Won; Song, Seung Ryel; Park, Do-Sim; So, Hong-Seob; Park, Raekil

    2013-12-06

    Highlights: •A fasting–refeeding high fat diet (HDF) model mimics irregular eating habit. •A fasting–refeeding HFD induces liver ballooning injury. •A fasting–refeeding HDF process elicits hepatic triglyceride accumulation. •Fenofibrate, PPARα ligand, prevents liver damage induced by refeeding HFD. -- Abstract: Fenofibrate, a peroxisome proliferator-activated receptor α (PPARα) agonist, is an anti-hyperlipidemic agent that has been widely used in the treatment of dyslipidemia. In this study, we examined the effect of fenofibrate on liver damage caused by refeeding a high-fat diet (HFD) in mice after 24 h fasting. Here, we showed that refeeding HFD after fasting causes liver damage in mice determined by liver morphology and liver cell death. A detailed analysis revealed that hepatic lipid droplet formation is enhanced and triglyceride levels in liver are increased by refeeding HFD after starvation for 24 h. Also, NF-κB is activated and consequently induces the expression of TNF-α, IL1-β, COX-2, and NOS2. However, treating with fenofibrate attenuates the liver damage and triglyceride accumulation caused by the fasting–refeeding HFD process. Fenofibrate reduces the expression of NF-κB target genes but induces genes for peroxisomal fatty acid oxidation, peroxisome biogenesis and mitochondrial fatty acid oxidation. These results strongly suggest that the treatment of fenofibrate ameliorates the liver damage induced by fasting–refeeding HFD, possibly through the activation of fatty acid oxidation.

  10. Identification of transcriptional networks involved in peroxisome proliferator chemical-induced hepatocyte proliferation

    EPA Science Inventory

    Peroxisome proliferator chemical (PPC) exposure leads to increases in rodent liver tumors through a non-genotoxic mode of action (MOA). The PPC MOA includes increased oxidative stress, hepatocyte proliferation and decreased apoptosis. We investigated the putative genetic regulato...

  11. Differential Roles of Smad1 and p38 Kinase in Regulation of Peroxisome Proliferator-activating Receptor γ during Bone Morphogenetic Protein 2-induced Adipogenesis

    PubMed Central

    Hata, Kenji; Nishimura, Riko; Ikeda, Fumiyo; Yamashita, Kenji; Matsubara, Takuma; Nokubi, Takashi; Yoneda, Toshiyuki

    2003-01-01

    Bone morphogenetic protein 2 (BMP2) promotes the differentiation of undifferentiated mesenchymal cells into adipocytes. To investigate the molecular mechanisms that regulate this differentiation process, we studied the relationship between BMP2 signaling and peroxisome proliferator-activating receptor γ (PPARγ) during adipogenesis of mesenchymal cells by using pluripotent mesenchymal cell line C3H10T1/2. In C3H10T1/2 cells, BMP2 induced expression of PPARγ along with adipogenesis. Overexpression of Smad6, a natural antagonist for Smad1, blocked PPARγ expression and adipocytic differentiation induced by BMP2. Overexpression of dominant-negative PPARγ also diminished adipocytic differentiation of C3H10T1/2 cells, suggesting the central role of PPARγ in BMP2-induced adipocytic differentiation. Specific inhibitors for p38 kinase inhibited BMP2-induced adipocytic differentiation and transcriptional activation of PPARγ, whereas overexpression of Smad6 had no effect on transcriptional activity of PPARγ. Furthermore, activation of p38 kinase by overexpression of TAK1 and TAB1, without affecting PPARγ expression, led the up-regulation of transcriptional activity of PPARγ. These results suggest that both Smad and p38 kinase signaling are concomitantly activated and responsible for BMP2-induced adipocytic differentiation by inducing and up-regulating PPARγ, respectively. Thus, BMP2 controls adipocytic differentiation by using two distinct signaling pathways that play differential roles in this process in C3H10T1/2 cells. PMID:12589053

  12. Peroxisome proliferator-activated receptor γ attenuates serotonin-induced pulmonary artery smooth muscle cell proliferation and apoptosis inhibition involving ERK1/2 pathway.

    PubMed

    Han, Xinyuan; Chen, Chunyan; Cheng, Gong; Liang, Lei; Yao, Xiaowei; Yang, Guang; You, Penghua; Shou, Xiling

    2015-07-01

    Serotonin (5-HT) has been shown to be involved in pulmonary vascular remodeling in pulmonary arterial hypertension (PAH) by inducing pulmonary artery smooth muscle cells (PASMCs) proliferation and inhibiting PASMC apoptosis. Peroxisome proliferator-activated receptor γ (PPARγ) plays a crucial role in regulating proliferation and apoptosis of many cell types. Moreover, recently, loss of PPARγ has also been reported to be associated with the development of PAH. The present study is aimed to assess whether PPARγ is involved in 5-HT induced PASMC proliferation and apoptosis inhibition and the possible mechanism. We found that 5-HT could induce PASMC proliferation and inhibit PASMC apoptosis in a dose-dependent manner. Furthermore, we found that 5-HT negatively regulated PPARγ expression and gene promoter activity in PASMCs and 5-HT induced PASMC proliferation and apoptosis resistance could be abolished by PPARγ agonists and enhanced by PPARγ inhibitor. In addition, we found that extracellular signal-regulated kinase (ERK) signaling pathway mediated the 5-HT-induced inhibition of PPARγ expression. Our results might provide novel insights into the mechanisms for the pro-remodeling action of 5-HT in pulmonary vasculature.

  13. Peroxisome Proliferator–Activated Receptor α Protects Renal Tubular Cells from Gentamicin-Induced Apoptosis via Upregulating Na+/H+ Exchanger NHE1

    PubMed Central

    Chen, Cheng-Hsien; Chen, Tso-Hsiao; Wu, Mei-Yi; Chen, Jia-Rung; Hong, Li-Yu; Zheng, Cai-Mei; Chiu, I-Jen; Lin, Yuh-Feng; Hsu, Yung-Ho

    2015-01-01

    Peroxisome proliferator–activated receptor (PPAR)-α is a transcription factor that has been reported to inhibit gentamicin-induced apoptosis in renal tubular cells. However, the antiapoptotic mechanism of PPARα is still unknown. In this study, we found that PPARα overexpression induced Na+/H+ exchanger-1 (NHE1) expression in the rat renal tubular cells NRK-52E. Beraprost, a PPARα ligand, also increased NHE1 expression in the renal tubules in normal mice, but not in PPARα knockout mice. Chromatin immunoprecipitation assays revealed that two PPARα binding elements were located in the rat NHE1 promoter region. Na+/H+ exchanger activity also increased in the PPARα-overexpressed cells. Flow cytometry showed that the PPARα-overexpressed cells were resistant to apoptosis-induced shrinkage. Cariporide, a selective NHE1 inhibitor, inhibited the antiapoptotic effect of PPARα in the gentamicin-treated cells. The interaction between NHE1 and ezrin/radixin/moesin (ERM) and between ERM and phosphatidylinositol 4,5-bisphosphate in the PPARα-overexpressed cells was more than in the control cells. ERM short interfering RNA (siRNA) transfection inhibited the PPARα-induced antiapoptotic effect. PPARα overexpression also increased the phosphoinositide 3-kinase (PI3K) expression, which is dependent on NHE1 activity. Increased PI3K further increased the phosphorylation of the prosurvival kinase Akt in the PPARα-overexpressed cells. Wortmannin, a PI3K inhibitor, inhibited PPARα-induced Akt activity and the antiapoptotic effect. We conclude that PPARα induces NHE1 expression and then recruits ERM to promote PI3K/Akt-mediated cell survival in renal tubular cells. The application of PPARα activation reduces the nephrotoxicity of gentamicin and may expand the clinical use of gentamicin. PMID:26623927

  14. Optical Control of Peroxisomal Trafficking.

    PubMed

    Spiltoir, Jessica I; Strickland, Devin; Glotzer, Michael; Tucker, Chandra L

    2016-07-15

    The blue-light-responsive LOV2 domain of Avena sativa phototropin1 (AsLOV2) has been used to regulate activity and binding of diverse protein targets with light. Here, we used AsLOV2 to photocage a peroxisomal targeting sequence, allowing light regulation of peroxisomal protein import. We generated a protein tag, LOV-PTS1, that can be appended to proteins of interest to direct their import to the peroxisome with light. This method provides a means to inducibly trigger peroxisomal protein trafficking in specific cells at user-defined times. PMID:26513473

  15. Role of peroxisome proliferator-activated receptor-α in acute pancreatitis induced by cerulein

    PubMed Central

    Genovese, Tiziana; Mazzon, Emanuela; Di Paola, Rosanna; Muià, Carmelo; Crisafulli, Concetta; Malleo, Giuseppe; Esposito, Emanuela; Cuzzocrea, Salvatore

    2006-01-01

    The peroxisome proliferator-activated receptor-α (PPAR-α) is a member of the nuclear receptor superfamily of ligand-dependent transcription factors related to retinoid, steroid and thyroid hormone receptors. The aim of the present study was to examine the effects of endogenous PPAR-α ligand on the development of acute pancreatitis caused by cerulein in mice. Intraperitoneal injection of cerulein into PPAR-α wild-type (WT) mice resulted in severe, acute pancreatitis characterized by oedema, neutrophil infiltration and necrosis and by elevated serum levels of amylase and lipase. Infiltration of pancreatic and lung tissue with neutrophils (measured as an increase in myeloperoxidase activity) was associated with enhanced expression of the adhesion molecules intercellular adhesion molecule-1 (ICAM-1) and P-selectin. Immunohistochemical examination demonstrated a marked increase in the staining (immunoreactivity) for transforming growth factor-β (TGF-β) and vascular endothelial growth factor (VEGF) in the pancreas of cerulein-treated PPAR-α wild-type (WT) mice in comparison to sham-treated mice. Acute pancreatitis in PPAR-αWT mice was also associated with a significant mortality (20% survival at 5 days after cerulein administration). In contrast, the degree of pancreatic inflammation and tissue injury (histological score), up-regulation/formation of ICAM-1 and P-selectin, infiltration of neutrophils, and the expression of TGF-β and VEGF was markedly enhanced in pancreatic tissue obtained from cerulein-treated PPAR-α knockout (KO) mice. Thus, endogenous PPAR-α ligands reduce the degree of pancreas injury caused by acute pancreatitis induced by cerulein administration. PMID:16764691

  16. Nimesulide, a cyclooxygenase-2 selective inhibitor, suppresses obesity-related non-alcoholic fatty liver disease and hepatic insulin resistance through the regulation of peroxisome proliferator-activated receptor γ

    PubMed Central

    Tsujimoto, Shunsuke; Kishina, Manabu; Koda, Masahiko; Yamamoto, Yasutaka; Tanaka, Kohei; Harada, Yusuke; Yoshida, Akio; Hisatome, Ichiro

    2016-01-01

    Cyclooxygenase (COX)-2 selective inhibitors suppress non-alcoholic fatty liver disease (NAFLD); however, the precise mechanism of action remains unknown. The aim of this study was to examine how the COX-2 selective inhibitor nimesulide suppresses NAFLD in a murine model of high-fat diet (HFD)-induced obesity. Mice were fed either a normal chow diet (NC), an HFD, or HFD plus nimesulide (HFD-nime) for 12 weeks. Body weight, hepatic COX-2 mRNA expression and triglyceride accumulation were significantly increased in the HFD group. Triglyceride accumulation was suppressed in the HFD-nime group. The mRNA expression of hepatic peroxisome proliferator-activated receptor γ (PPARγ) and the natural PPARγ agonist 15-deoxy-Δ12,14-prostaglandin J2 (15d-PGJ2) were significantly increased in the HFD group and significantly suppressed in the HFD-nime group. Glucose metabolism was impaired in the HFD group compared with the NC group, and it was significantly improved in the HFD-nime group. In addition, the plasma insulin levels in the HFD group were increased compared with those in the NC group, and were decreased in the HFD-nime group. These results indicate that HFD-induced NAFLD is mediated by the increased hepatic expression of COX-2. We suggest that the production of 15d-PGJ2, which is mediated by COX-2, induces NAFLD and hepatic insulin resistance by activating PPARγ. Furthermore, the mRNA expression of tissue inhibitor of metalloproteinases-1 (TIMP-1), procollagen-1 and monocyte chemoattractant protein-1 (MCP-1), as well as the number of F4/80-positive hepatic (Kupffer) cells, were significantly increased in the HFD group compared with the NC group, and they were reduced by nimesulide. In conclusion, COX-2 may emerge as a molecular target for preventing the development of NAFLD and insulin resistance in diet-related obesity. PMID:27431935

  17. Peroxisomes in cardiomyocytes and the peroxisome / peroxisome proliferator-activated receptor-loop.

    PubMed

    Colasante, Claudia; Chen, Jiangping; Ahlemeyer, Barbara; Baumgart-Vogt, Eveline

    2015-03-01

    It is well established that the heart is strongly dependent on fatty acid metabolism. In cardiomyocytes there are two distinct sites for the β-oxidisation of fatty acids: the mitochondrion and the peroxisome. Although the metabolism of these two organelles is believed to be tightly coupled, the nature of this relationship has not been fully investigated. Recent research has established the significant contribution of mitochondrial function to cardiac ATP production under normal and pathological conditions. In contrast, limited information is available on peroxisomal function in the heart. This is despite these organelles harbouring metabolic pathways that are potentially cardio-protective, and findings that patients with peroxisomal diseases, such as adult Refsum´s disease, can develop heart failure. In this article, we provide a comprehensive overview on the current knowledge of peroxisomes and the regulation of lipid metabolism by PPARs in cardiomyocytes. We also present new experimental evidence on the differential expression of peroxisome-related genes in the heart chambers and demonstrate that even a mild peroxisomal biogenesis defect (Pex11α-/-) can induce profound alterations in the cardiomyocyte´s peroxisomal compartment and related gene expression, including the concomitant deregulation of specific PPARs. The possible impact of peroxisomal dysfunction in the heart is discussed and a model for the modulation of myocardial metabolism via a peroxisome/PPAR-loop is proposed.

  18. [Peroxisomal diseases--a survey].

    PubMed

    Theron, J J; van Papendorp, D H

    1996-06-01

    intermediates, phytanic acid, pipecolic acid and plasmalogens. Therapy includes dietary adjustments e.g. supplementation with oleic acid derivatives to normalise elevated VLCFAs in XALD. Treatment with hypolipidaemic drugs and certain peroxisomal substrates which induce proliferation of mature peroxisomes offers promise in the therapy of these debilitating and often fatal diseases.

  19. Identification of a peroxisome proliferator responsive element (PPRE)-like cis-element in mouse plasminogen activator inhibitor-1 gene promoter

    SciTech Connect

    Chen Jiegen; Li Xi; Huang Haiyan; Liu Honglei; Liu Deguo; Song Tanjing; Ma Chungu; Ma Duan; Song Houyan; Tang Qiqun . E-mail: qqtang@shmu.edu.cn

    2006-09-01

    PAI-1 is expressed and secreted by adipose tissue which may mediate the pathogenesis of obesity-associated cardiovascular complications. Evidence is presented in this report that PAI-1 is not expressed by preadipocyte, but significantly induced during 3T3-L1 adipocyte differentiation and the PAI-1 expression correlates with the induction of peroxisome proliferator-activated receptor {gamma} (PPAR{gamma}). A peroxisome proliferator responsive element (PPRE)-like cis-element (-206TCCCCCATGCCCT-194) is identified in the mouse PAI-1 gene promoter by electrophoretic mobility shift assay (EMSA) combined with transient transfection experiments; the PPRE-like cis-element forms a specific DNA-protein complex only with adipocyte nuclear extracts, not with preadipocyte nuclear extracts; the DNA-protein complex can be totally competed away by non-labeled consensus PPRE, and can be supershifted with PPAR{gamma} antibody. Mutation of this PPRE-like cis-element can abolish the transactivation of mouse PAI-1 promoter mediated by PPAR{gamma}. Specific PPAR{gamma} ligand Pioglitazone can significantly induce the PAI-1 expression, and stimulate the secretion of PAI-1 into medium.

  20. Yeast peroxisomes: structure, functions and biotechnological opportunities.

    PubMed

    Sibirny, Andriy A

    2016-06-01

    Peroxisomes are ubiquitous organelles found in most eukaryotic cells. In yeasts, peroxisomes play important roles in cell metabolism, especially in different catabolic processes including fatty acid β-oxidation, the glyoxylic shunt and methanol metabolism, as well as some biosynthetic processes. In addition, peroxisomes are the compartment in which oxidases and catalase are localized. New peroxisomes mainly arise by fission of pre-existing ones, although they can also be formed from the endoplasmic reticulum (ER). Peroxisomes consist of matrix-soluble proteins and membrane proteins known as peroxins. A total of 34 PEX peroxin genes and proteins have been identified to date. and their functions have been elucidated. Protein import into peroxisomes depends on peroxins and requires specific signals in the structure of transported proteins: PTS1, PTS2 and mPTS. The mechanisms of metabolite penetration into peroxisomes are still poorly understood. Peroxisome number and the volume occupied by these organelles are tightly regulated. Methanol, fatty acids and methylamine act as efficient peroxisome proliferators, whereas glucose and ethanol induce peroxisome autophagic degradation (pexophagy). To date, 42 Atg proteins involved in pexophagy are known. Catabolism and alcoholic fermentation of the major pentose sugar, xylose, depend on peroxisomal enzymes. Overexpression of peroxisomal transketolase and transaldolase activates xylose fermentation. Peroxisomes could be useful as target organelles for overexpression of foreign toxic proteins. PMID:27189367

  1. Inducible Conditional Vascular-Specific Overexpression of Peroxisome Proliferator-Activated Receptor Beta/Delta Leads to Rapid Cardiac Hypertrophy

    PubMed Central

    Wagner, Kay-Dietrich; Vukolic, Ana; Baudouy, Delphine; Michiels, Jean-François

    2016-01-01

    Peroxisome proliferator-activated receptors are nuclear receptors which function as ligand-activated transcription factors. Among them, peroxisome proliferator-activated receptor beta/delta (PPARβ/δ) is highly expressed in the heart and thought to have cardioprotective functions due to its beneficial effects in metabolic syndrome. As we already showed that PPARβ/δ activation resulted in an enhanced cardiac angiogenesis and growth without impairment of heart function, we were interested to determine the effects of a specific activation of PPARβ/δ in the vasculature on cardiac performance under normal and in chronic ischemic heart disease conditions. We analyzed the effects of a specific PPARβ/δ overexpression in endothelial cells on the heart using an inducible conditional vascular-specific mouse model. We demonstrate that vessel-specific overexpression of PPARβ/δ induces rapid cardiac angiogenesis and growth with an increase in cardiomyocyte size. Upon myocardial infarction, vascular overexpression of PPARβ/δ, despite the enhanced cardiac vessel formation, does not protect against chronic ischemic injury. Our results suggest that the proper balance of PPARβ/δ activation in the different cardiac cell types is required to obtain beneficial effects on the outcome in chronic ischemic heart disease. PMID:27057154

  2. Peroxisome proliferator-activated receptor alpha induction of uncoupling protein 2 protects against acetaminophen-induced liver toxicity.

    PubMed

    Patterson, Andrew D; Shah, Yatrik M; Matsubara, Tsutomu; Krausz, Kristopher W; Gonzalez, Frank J

    2012-07-01

    Acetaminophen (APAP) overdose causes acute liver failure in humans and rodents due in part to the destruction of mitochondria as a result of increased oxidative stress followed by hepatocellular necrosis. Activation of the peroxisome proliferator-activated receptor alpha (PPARα), a member of the nuclear receptor superfamily that controls the expression of genes encoding peroxisomal and mitochondrial fatty acid β-oxidation enzymes, with the experimental ligand Wy-14,643 or the clinically used fibrate drug fenofibrate, fully protects mice from APAP-induced hepatotoxicity. PPARα-humanized mice were also protected, whereas Ppara-null mice were not, thus indicating that the protection extends to human PPARα and is PPARα-dependent. This protection is due in part to induction of the PPARα target gene encoding mitochondrial uncoupling protein 2 (UCP2). Forced overexpression of UCP2 protected wildtype mice against APAP-induced hepatotoxicity in the absence of PPARα activation. Ucp2-null mice, however, were sensitive to APAP-induced hepatotoxicity despite activation of PPARα with Wy-14,643. Protection against hepatotoxicity by UCP2-induction through activation of PPARα is associated with decreased APAP-induced c-jun and c-fos expression, decreased phosphorylation of JNK and c-jun, lower mitochondrial H(2)O(2) levels, increased mitochondrial glutathione in liver, and decreased levels of circulating fatty acyl-carnitines. These studies indicate that the PPARα target gene UCP2 protects against elevated reactive oxygen species generated during drug-induced hepatotoxicity and suggest that induction of UCP2 may also be a general mechanism for protection of mitochondria during fatty acid β-oxidation.

  3. The role of peroxisome proliferator-activated receptor-{beta}/{delta} in epidermal growth factor-induced HaCaT cell proliferation

    SciTech Connect

    Liang Pengfei; Jiang Bimei; Yang Xinghua; Xiao Xianzhong Huang Xu; Long Jianhong; Zhang Pihong; Zhang Minghua; Xiao Muzhang; Xie Tinghong; Huang Xiaoyuan

    2008-10-15

    Epidermal growth factor (EGF) has been shown to be a potent mitogen for epidermal cells both in vitro and in vivo, thus contributing to the development of an organism. It has recently become clear that peroxisome proliferator-activated receptor-{beta}/{delta} (PPAR{beta}/{delta}) expression and activation is involved in the cell proliferation. However, little is known about the role of PPAR{beta}/{delta} in EGF-induced proliferation of HaCaT keratinocytes. In this study, HaCaT cells were cultured in the presence and absence of EGF and we identified that EGF induced an increase of PPAR{beta}/{delta} mRNA and protein level expression in time-dependent and dose-dependent manner, and AG1487, an EGF receptor (EGFR) special inhibitor, caused attenuation of PPAR{beta}/{delta} protein expression. Electrophoretic mobility shift assay (EMSA) revealed that EGF significantly increased PPAR{beta}/{delta} binding activity in HaCaT keratinocytes. Antisense phosphorothioate oligonucleotides (asODNs) against PPAR{beta}/{delta} caused selectively inhibition of PPAR{beta}/{delta} protein content induced by EGF and significantly attenuated EGF-mediated cell proliferation. Treatment of the cells with L165041, a specific synthetic ligand for PPAR{beta}/{delta}, significantly enhanced EGF-mediated cell proliferation. Finally, c-Jun ablation inhibited PPAR{beta}/{delta} up-regulation induced by EGF, and chromatin immunoprecipitation (ChIP) showed that c-Jun bound to the PPAR{beta}/{delta} promoter and the binding increased in EGF-stimulated cells. These results demonstrate that EGF induces PPAR{beta}/{delta} expression in a c-Jun-dependent manner and PPAR{beta}/{delta} plays a vital role in EGF-stimulated proliferation of HaCaT cells.

  4. MicroRNA-128 inhibition attenuates myocardial ischemia/reperfusion injury-induced cardiomyocyte apoptosis by the targeted activation of peroxisome proliferator-activated receptor gamma

    PubMed Central

    ZENG, XIAO CONG; LI, LANG; WEN, HONG; BI, QI

    2016-01-01

    The aim of the present study was to investigate the effects of microRNA (miR)-128 inhibition on the targeted activation of peroxisome proliferator-activated receptor gamma (PPARG) and on cardiomyocyte apoptosis induced by myocardial ischemia/reperfusion (I/R) injury. In vitro, the expression of PPARG was detected by reverse transcription-quantitative polymerase chain reaction and western blotting in neonatal rat ventricular myocytes (NRVMs) and HEK293 cells transfected with the mimics or inhibitors of miR-128 or control RNA. Luciferase reporter assays were used to identify whether PPARG is a direct target of miR-128. In vivo, miR-128 was knocked down via ear vein injection of antagomir-128 in a rabbit myocardial I/R injury model. Western blotting investigated the activation of Akt [phosphorylated (p)-Akt] and the expression of total-Akt, PPARG and myeloid leukemia cell differentiation protein-1 (Mcl-1) in the myocardium. Cardiomyocyte apoptosis was examined with transmission electron microscropy and terminal deoxynucleotidyl transferase dUTP nick end labeling staining. PPARG mRNA and protein were downregulated in NRVMs transfected with miR-128 mimics, but upregulated by antagomir-128 compared with control. This indicates that PPARG is a direct miR-128 target. Activation of Akt (p-Akt), Mcl-1 and PPARG expression in the myocardium were increased by miR-128 inhibition. Furthermore, miR-128 antagomirs significantly reduced apoptosis in hearts subjected to I/R injury, which was blocked by the PPARG inhibitor GW9662. In conclusion, miR-128 inhibition attenuated I/R injury-induced cardiomyocyte apoptosis by the targeted activation of PPARG signaling. PMID:27150726

  5. Redox regulated peroxisome homeostasis.

    PubMed

    Wang, Xiaofeng; Li, Shuo; Liu, Yu; Ma, Changle

    2015-01-01

    Peroxisomes are ubiquitous organelles present in nearly all eukaryotic cells. Conserved functions of peroxisomes encompass beta-oxidation of fatty acids and scavenging of reactive oxygen species generated from diverse peroxisomal metabolic pathways. Peroxisome content, number, and size can change quickly in response to environmental and/or developmental cues. To achieve efficient peroxisome homeostasis, peroxisome biogenesis and degradation must be orchestrated. We review the current knowledge on redox regulated peroxisome biogenesis and degradation with an emphasis on yeasts and plants.

  6. Redox regulated peroxisome homeostasis.

    PubMed

    Wang, Xiaofeng; Li, Shuo; Liu, Yu; Ma, Changle

    2015-01-01

    Peroxisomes are ubiquitous organelles present in nearly all eukaryotic cells. Conserved functions of peroxisomes encompass beta-oxidation of fatty acids and scavenging of reactive oxygen species generated from diverse peroxisomal metabolic pathways. Peroxisome content, number, and size can change quickly in response to environmental and/or developmental cues. To achieve efficient peroxisome homeostasis, peroxisome biogenesis and degradation must be orchestrated. We review the current knowledge on redox regulated peroxisome biogenesis and degradation with an emphasis on yeasts and plants. PMID:25545794

  7. Activation of Peroxisome Proliferator-Activated Receptor-γ Reverses Squamous Metaplasia and Induces Transitional Differentiation in Normal Human Urothelial Cells

    PubMed Central

    Varley, Claire Lucy; Stahlschmidt, Jens; Smith, Barbara; Stower, Michael; Southgate, Jennifer

    2004-01-01

    We observed that in urothelium, both cornifying and noncornifying forms of squamous metaplasia are accompanied by changes in the localization of the nuclear hormone receptors, peroxisome proliferator activated receptor γ (PPAR-γ) and retinoid X receptor (RXR-α). To obtain objective evidence for a role for PPAR-γ-mediated signaling in urothelial differentiation, we examined expression of the cytokeratin isotypes CK13, CK20, and CK14 as indicators of transitional, terminal transitional, and squamous differentiation, respectively, in cultures of normal human urothelial cells. In control culture conditions, normal human urothelial cells showed evidence of squamous differentiation (CK14+, CK13−, CK20−). Treatment with the high-affinity PPAR-γ agonist, troglitazone (TZ), resulted in gain of CK13 and loss of CK14 protein expression. The effect of TZ was significantly augmented when the autocrine-stimulated epidermal growth factor receptor pathway was inhibited and this resulted in induction of CK20 expression. The RXR-specific inhibitors PA452, HX531, and HX603 inhibited the TZ-induced CK13 expression, supporting a role for RXR in the induction of CK13 expression. Thus, signaling through PPAR-γ can mediate transitional differentiation of urothelial cells and this is modulated by growth regulatory programs. PMID:15111325

  8. Highly oxidized peroxisomes are selectively degraded via autophagy in Arabidopsis.

    PubMed

    Shibata, Michitaro; Oikawa, Kazusato; Yoshimoto, Kohki; Kondo, Maki; Mano, Shoji; Yamada, Kenji; Hayashi, Makoto; Sakamoto, Wataru; Ohsumi, Yoshinori; Nishimura, Mikio

    2013-12-01

    The positioning of peroxisomes in a cell is a regulated process that is closely associated with their functions. Using this feature of the peroxisomal positioning as a criterion, we identified three Arabidopsis thaliana mutants (peroxisome unusual positioning1 [peup1], peup2, and peup4) that contain aggregated peroxisomes. We found that the PEUP1, PEUP2, and PEUP4 were identical to Autophagy-related2 (ATG2), ATG18a, and ATG7, respectively, which are involved in the autophagic system. The number of peroxisomes was increased and the peroxisomal proteins were highly accumulated in the peup1 mutant, suggesting that peroxisome degradation by autophagy (pexophagy) is deficient in the peup1 mutant. These aggregated peroxisomes contained high levels of inactive catalase and were more oxidative than those of the wild type, indicating that peroxisome aggregates comprise damaged peroxisomes. In addition, peroxisome aggregation was induced in wild-type plants by exogenous application of hydrogen peroxide. The cat2 mutant also contained peroxisome aggregates. These findings demonstrate that hydrogen peroxide as a result of catalase inactivation is the inducer of peroxisome aggregation. Furthermore, an autophagosome marker, ATG8, frequently colocalized with peroxisome aggregates, indicating that peroxisomes damaged by hydrogen peroxide are selectively degraded by autophagy in the wild type. Our data provide evidence that autophagy is crucial for quality control mechanisms for peroxisomes in Arabidopsis.

  9. Impacts of peroxisome proliferator-activated receptor-γ activation on cigarette smoke-induced exacerbated response to bacteria.

    PubMed

    Morissette, Mathieu C; Shen, Pamela; Thayaparan, Danya; Stämpfli, Martin R

    2015-01-01

    Chronic obstructive pulmonary disease (COPD) is characterised by a state of chronic pulmonary inflammation punctuated by microbial exacerbations. Despite advances in treatment options, COPD remains difficult to manage. In this study, we investigated the potential of peroxisome proliferator-activated receptor (PPAR)γ activation as a new therapy against cigarette smoke-induced inflammation and its associated bacterial exacerbation. C57BL/6 mice were exposed to room air or cigarette smoke for either 4 days or 4 weeks and treated either prophylactically or therapeutically with rosiglitazone. The impact of rosiglitazone on cigarette smoke-induced exacerbated response to the bacterial pathogen nontypeable Haemophilus influenzae (NTHi) was studied using the therapeutic treatment protocol. We found that rosiglitazone was able to reduce cigarette smoke-induced neutrophilia both when administered prophylactically or therapeutically. Therapeutic intervention with rosiglitazone was also effective in preventing cigarette smoke-induced neutrophilia exacerbation following NTHi infection. Moreover, the anti-inflammatory effects of rosiglitazone did not lead to an increase in the pulmonary bacterial burden, unlike dexamethasone. Altogether, our data suggest that pharmacological activation of PPARγ may be an effective therapeutic approach to improve COPD management, as it is able to reduce cigarette smoke-induced inflammation and decrease the magnitude of bacterial exacerbations, without compromising the ability of the immune system to control the infection. PMID:25034559

  10. Peroxisome deficiency-induced ER stress and SREBP-2 pathway activation in the liver of newborn PEX2 knock-out mice.

    PubMed

    Kovacs, Werner J; Charles, Khanichi N; Walter, Katharina M; Shackelford, Janis E; Wikander, Thomas M; Richards, Michael J; Fliesler, Steven J; Krisans, Skaidrite K; Faust, Phyllis L

    2012-06-01

    Disruption of the Pex2 gene leads to peroxisome deficiency and widespread metabolic dysfunction. We previously demonstrated that peroxisomes are critical for maintaining cholesterol homeostasis, using peroxisome-deficient Pex2(-/-) mice on a hybrid Swiss Webster×129S6/SvEv (SW/129) genetic background. Peroxisome deficiency activates hepatic endoplasmic reticulum (ER) stress pathways, leading to dysregulation of the endogenous sterol response mechanism. Herein, we demonstrate a more profound dysregulation of cholesterol homeostasis in newborn Pex2(-/-) mice congenic on a 129S6/SvEv (129) genetic background, and substantial differences between newborn versus postnatal Pex2(-/-) mice in factors that activate ER stress. These differences extend to relationships between activation of genes regulated by SREBP-2 versus PPARα. The SREBP-2 pathway is induced in neonatal Pex2(-/-) livers from 129 and SW/129 strains, despite normal hepatic cholesterol levels. ER stress markers are increased in newborn 129 Pex2(-/-) livers, which occurs in the absence of hepatic steatosis or accumulation of peroxins in the ER. Moreover, the induction of SREBP-2 and ER stress pathways is independent of PPARα activation in livers of newborn 129 and SW/129 Pex2(-/-) mice. Two-week-old wild-type mice treated with the peroxisome proliferator WY-14,643 show strong induction of PPARα-regulated genes and decreased expression of SREBP-2 and its target genes, further demonstrating that SREBP-2 pathway induction is not dependent on PPARα activation. Lastly, there is no activation of either SREBP-2 or ER stress pathways in kidney and lung of newborn Pex2(-/-) mice, suggesting a parallel induction of these pathways in peroxisome-deficient mice. These findings establish novel associations between SREBP-2, ER stress and PPARα pathway inductions.

  11. Expression of Peroxisome Proliferator-Activated Receptor γ (PPARγ) in Human Transitional Bladder Cancer and its Role in Inducing Cell Death1

    PubMed Central

    Guan, You-Fei; Zhang, Ya-Hua; Breyer, Richard M; Davis, Linda; Breyer, Matthew D

    1999-01-01

    Abstract The present study examined the expression and role of the thiazolidinedione (TZD)-activated transcription factor, peroxisome proliferator-activated receptor γ (PPARγ), in human bladder cancers. In situ hybridization shows that PPARγ mRNA is highly expressed in all human transitional epithelial cell cancers (TCCa's) studied (n=11). PPARγ was also expressed in five TCCa cell lines as determined by RNase protection assays and immunoblot. Retinoid X receptor α (RXRα), a 9-cis-retinoic acid stimulated (9-cis-RA) heterodimeric partner of PPARγ, was also co-expressed in all TCCa tissues and cell lines. Treatment of the T24 bladder cancer cells with the TZD PPARγ agonist troglitazone, dramatically inhibited 3H-thymidine incorporation and induced cell death. Addition of the RXRα ligands, 9-cis-RA or LG100268, sensitized T24 bladder cancer cells to the lethal effect of troglitazone and two other PPARγ activators, ciglitazone and 15-deoxy-Δ2,14-PGJ2 (15dPGJ2). Troglitazone treatment increased expression of two cyclin-dependent kinase inhibitors, P21WAF1/CIP1 and p16INK4, and reduced cyclin D1 expression, consistent with G1 arrest. Troglitazone also induced an endogenous PPARγ target gene in T24 cells, adipocyte-type fatty acid binding protein (A-FABP), the expression of which correlates with bladder cancer differentiation. In situ hybridization shows that A-FABP expression is localized to normal uroepithelial cells as well as some TCCa's. Taken together, these results demonstrate that PPARγ is expressed in human TCCa where it may play a role in regulating TCCa differentiation and survival, thereby providing a potential target for therapy of uroepithelial cancers. PMID:10935488

  12. Activation of Peroxisome Proliferator-activated Receptor α Induces Lysosomal Biogenesis in Brain Cells

    PubMed Central

    Ghosh, Arunava; Jana, Malabendu; Modi, Khushbu; Gonzalez, Frank J.; Sims, Katherine B.; Berry-Kravis, Elizabeth; Pahan, Kalipada

    2015-01-01

    Lysosomes are ubiquitous membrane-enclosed organelles filled with an acidic interior and are central to the autophagic, endocytic, or phagocytic pathway. In contrast to its classical function as the waste management machinery, lysosomes are now considered to be an integral part of various cellular signaling processes. The diverse functionality of this single organelle requires a very complex and coordinated regulation of its activity with transcription factor EB (TFEB), a master regulator of lysosomal biogenesis, at its core. However, mechanisms by which TFEB is regulated are poorly understood. This study demonstrates that gemfibrozil, an agonist of peroxisome proliferator-activated receptor (PPAR) α, alone and in conjunction with all-trans-retinoic acid is capable of enhancing TFEB in brain cells. We also observed that PPARα, but not PPARβ and PPARγ, is involved in gemfibrozil-mediated up-regulation of TFEB. Reporter assay and chromatin immunoprecipitation studies confirmed the recruitment of retinoid X receptor α, PPARα, and PGC1α on the PPAR-binding site on the Tfeb promoter as well. Subsequently, the drug-mediated induction of TFEB caused an increase in lysosomal protein and the lysosomal abundance in cell. Collectively, this study reinforces the link between lysosomal biogenesis and lipid metabolism with TFEB at the crossroads. Furthermore, gemfibrozil may be of therapeutic value in the treatment of lysosomal storage disorders in which autophagy-lysosome pathway plays an important role. PMID:25750174

  13. Antioxidant cytoprotection by peroxisomal peroxiredoxin-5.

    PubMed

    Walbrecq, Geoffroy; Wang, Bo; Becker, Sarah; Hannotiau, Amandine; Fransen, Marc; Knoops, Bernard

    2015-07-01

    Peroxiredoxin-5 (PRDX5) is a thioredoxin peroxidase that reduces hydrogen peroxide, alkyl hydroperoxides, and peroxynitrite. This enzyme is present in the cytosol, mitochondria, peroxisomes, and nucleus in human cells. Antioxidant cytoprotective functions have been previously documented for cytosolic, mitochondrial, and nuclear mammalian PRDX5. However, the exact function of PRDX5 in peroxisomes is still not clear. The aim of this work was to determine the function of peroxisomal PRDX5 in mammalian cells and, more specifically, in glial cells. To study the role of PRDX5 in peroxisomes, the endogenous expression of PRDX5 in murine oligodendrocyte 158N cells was silenced by RNA interference. In addition, human PRDX5 was also overexpressed in peroxisomes using a vector coding for human PRDX5, whose unconventional peroxisomal targeting sequence 1 (PTS1; SQL) was replaced by the prototypical PTS1 SKL. Stable 158N clones were obtained. The antioxidant cytoprotective function of peroxisomal PRDX5 against peroxisomal and mitochondrial KillerRed-mediated reactive oxygen species production as well as H2O2 was examined using MTT viability assays, roGFP2, and C11-BOBIPY probes. Altogether our results show that peroxisomal PRDX5 protects 158N oligodendrocytes against peroxisomal and mitochondrial KillerRed- and H2O2-induced oxidative stress. PMID:25772011

  14. Peroxisome proliferator-activated receptor β/δ induces myogenesis by modulating myostatin activity.

    PubMed

    Bonala, Sabeera; Lokireddy, Sudarsanareddy; Arigela, Harikumar; Teng, Serena; Wahli, Walter; Sharma, Mridula; McFarlane, Craig; Kambadur, Ravi

    2012-04-13

    Classically, peroxisome proliferator-activated receptor β/δ (PPARβ/δ) function was thought to be restricted to enhancing adipocyte differentiation and development of adipose-like cells from other lineages. However, recent studies have revealed a critical role for PPARβ/δ during skeletal muscle growth and regeneration. Although PPARβ/δ has been implicated in regulating myogenesis, little is presently known about the role and, for that matter, the mechanism(s) of action of PPARβ/δ in regulating postnatal myogenesis. Here we report for the first time, using a PPARβ/δ-specific ligand (L165041) and the PPARβ/δ-null mouse model, that PPARβ/δ enhances postnatal myogenesis through increasing both myoblast proliferation and differentiation. In addition, we have identified Gasp-1 (growth and differentiation factor-associated serum protein-1) as a novel downstream target of PPARβ/δ in skeletal muscle. In agreement, reduced Gasp-1 expression was detected in PPARβ/δ-null mice muscle tissue. We further report that a functional PPAR-responsive element within the 1.5-kb proximal Gasp-1 promoter region is critical for PPARβ/δ regulation of Gasp-1. Gasp-1 has been reported to bind to and inhibit the activity of myostatin; consistent with this, we found that enhanced secretion of Gasp-1, increased Gasp-1 myostatin interaction and significantly reduced myostatin activity upon L165041-mediated activation of PPARβ/δ. Moreover, we analyzed the ability of hGASP-1 to regulate myogenesis independently of PPARβ/δ activation. The results revealed that hGASP-1 protein treatment enhances myoblast proliferation and differentiation, whereas silencing of hGASP-1 results in defective myogenesis. Taken together these data revealed that PPARβ/δ is a positive regulator of skeletal muscle myogenesis, which functions through negatively modulating myostatin activity via a mechanism involving Gasp-1. PMID:22362769

  15. A widely used retinoic acid receptor antagonist induces peroxisome proliferator-activated receptor-gamma activity.

    PubMed

    Schupp, Michael; Curtin, Joshua C; Kim, Roy J; Billin, Andrew N; Lazar, Mitchell A

    2007-05-01

    Nuclear receptors (NRs) are transcription factors whose activity is regulated by the binding of small lipophilic ligands, including hormones, vitamins, and metabolites. Pharmacological NR ligands serve as important therapeutic agents; for example, all-trans retinoic acid, an activating ligand for retinoic acid receptor alpha (RARalpha), is used to treat leukemia. Another RARalpha ligand, (E)-S,S-dioxide-4-(2-(7-(heptyloxy)-3,4-dihydro-4,4-dimethyl-2H-1-benzothiopyran-6-yl)-1-propenyl)-benzoic acid (Ro 41-5253), is a potent antagonist that has been a useful and purportedly specific probe of RARalpha function. Here, we report that Ro 41-5253 also activates the peroxisome proliferator-activated receptor gamma (PPARgamma), a master regulator of adipocyte differentiation and target of widely prescribed antidiabetic thiazolidinediones (TZDs). Ro 41-5253 enhanced differentiation of mouse and human preadipocytes and activated PPARgamma target genes in mature adipocytes. Like the TZDs, Ro 41-5253 also down-regulated PPARgamma protein expression in adipocytes. In addition, Ro 41-5253 activated the PPARgamma-ligand binding domain in transiently transfected HEK293T cells. These effects were not prevented by a potent RARalpha agonist or by depleting cells of RARalpha, indicating that PPARgamma activation was not related to RARalpha antagonism. Indeed, Ro 41-5253 was able to compete with TZD ligands for binding to PPARgamma, suggesting that Ro 41-5253 directly affects PPAR activity. These results vividly demonstrate that pharmacological NR ligands may have "off-target" effects on other NRs. Ro 41-5253 is a PPARgamma agonist as well as an RARalpha antagonist whose pleiotropic effects on NRs may signify a unique spectrum of biological responses.

  16. Multiple Peroxisomal Enzymatic Deficiency Disorders

    PubMed Central

    Vamecq, Joseph; Draye, Jean-Pierre; Van Hoof, François; Misson, Jean-Paul; Evrard, Philippe; Verellen, Gaston; Eyssen, Hendrik J.; Van Eldere, Johan; Schutgens, Ruud B. H.; Wanders, Ronald J. A.; Roels, Frank; Goldfischer, Sidney L.

    1986-01-01

    Biologic, morphologic, and biochemical investigations performed in 2 patients demonstrate multiple peroxisomal deficiencies in the cerebrohepatorenal syndrome of Zellweger (CHRS) and neonatal adrenoleukodystrophy (NALD). Very long chain fatty acids, abnormal bile acids, including bile acid precursors (di- and trihydroxycoprostanoic acids), and C29-dicarboxylic acid accumulated in plasma in both patients. Generalized hyperaminoaciduria was also present. Peroxisomes could not be detected in CHRS liver and kidney; however, in the NALD patient, small and sparse cytoplasmic bodies resembling altered peroxisomes were found in hepatocytes. Hepatocellular and Kupffer cell lysosomes were engorged with ferritin and contained clefts and trilaminar structures believed to represent very long chain fatty acids. Enzymatic deficiencies reflected the peroxisomal defects. Hepatic glycolate oxidase and palmitoyl-CoA oxidase activities were deficient. No particle-bound catalase was found in cultured fibroblasts, and ether glycerolipid (plasmalogen) biosynthesis was markedly reduced. Administration of phenobarbital and clofibrate, an agent that induces peroxisomal proliferation and enzymatic activities, to the NALD patient did not bring about any changes in plasma metabolites, liver peroxisome population, or oxidizing activities. ImagesFigure 1Figure 2Figure 3Figure 4Figure 5 PMID:2879480

  17. Gemfibrozil modulates cytochrome P450 and peroxisome proliferation-inducible enzymes in the liver of the yellow European eel (Anguilla anguilla).

    PubMed

    Lyssimachou, Angeliki; Thibaut, Rémi; Gisbert, Enric; Porte, Cinta

    2014-01-01

    The human lipid regulator gemfibrozil (GEM) has been shown to induce peroxisome proliferation in rodents leading to hepatocarcinogenesis. Since GEM is found at biological active concentrations in the aquatic environment, the present study investigates the effects of this drug on the yellow European eel (Anguilla anguilla). Eels were injected with different concentrations of GEM (0.1 to 200 μg/g) and sampled 24- and 96-h post-injection. GEM was shown to inhibit CYP1A, CYP3A and CYP2K-like catalytic activities 24-h post-injection, but at 96-h post-injection, only CYP1A was significantly altered in fish injected with the highest GEM dose. On the contrary, GEM had little effect on the phase II enzymes examined (UDP-glucuronyltransferase and glutathione-S-transferase). Peroxisome proliferation inducible enzymes (liver peroxisomal acyl-CoA oxidase and catalase) were very weakly induced. No evidence of a significant effect on the endocrine system of eels was observed in terms of plasmatic steroid levels or testosterone esterification in the liver.

  18. Proton pump inhibitor-induced hypomagnesemic hypoparathyroidism.

    PubMed

    Swaminathan, Krishnan

    2015-01-01

    Proton pump inhibitors are the one of the most widely used drugs in the world. Hypomagnesemic hypoparathyroidism has been reported with different proton pump inhibitors with prolonged oral use. We report the first reported case of possible such effect with intravenous preparation of proton pump inhibitor. This case report raises awareness among physicians worldwide of this often unknown association, as life-threatening cardiac and neuromuscular complications can arise with unrecognized hypocalcemia and hypomagnesemia with proton pump inhibitors.

  19. The methylotrophic yeast Hansenula polymorpha contains an inducible import pathway for peroxisomal matrix proteins with an N-terminal targeting signal (PTS2 proteins).

    PubMed

    Faber, K N; Haima, P; Gietl, C; Harder, W; Ab, G; Veenhuis, M

    1994-12-20

    Two main types of peroxisomal targeting signals have been identified that reside either at the extreme C terminus (PTS1) or the N terminus (PTS2) of the protein. In the methylotrophic yeast Hansenula polymorpha the majority of peroxisomal matrix proteins are of the PTS1 type. Thus far, for H. polymorpha only amine oxidase (AMO) has been shown to contain a PTS2 type signal. In the present study we expressed H. polymorpha AMO under control of the strong endogenous alcohol oxidase promoter. Partial import of AMO into peroxisomes was observed in cells grown in methanol/(NH4)2SO4-containing medium. However, complete import of AMO occurred if the cells were grown under conditions that induce expression of the endogenous AMO gene. Similar results were obtained when the heterologous PTS2 proteins, glyoxysomal malate dehydrogenase from watermelon and thiolase from Saccharomyces cerevisiae, were synthesized in H. polymorpha. The import of PTS1 proteins, however, was not affected by the growth conditions. These results indicate that the reduced rate of AMO import in (NH4)2SO4-grown cells is not due to competition with PTS1 proteins for the same import pathway. Apparently, AMO is imported via a separate pathway that is induced by amines and functions for PTS2 proteins in general.

  20. Crosstalk between mitochondria and peroxisomes

    PubMed Central

    Demarquoy, Jean; Le Borgne, Françoise

    2015-01-01

    Mitochondria and peroxisomes are small ubiquitous organelles. They both play major roles in cell metabolism, especially in terms of fatty acid metabolism, reactive oxygen species (ROS) production, and ROS scavenging, and it is now clear that they metabolically interact with each other. These two organelles share some properties, such as great plasticity and high potency to adapt their form and number according to cell requirements. Their functions are connected, and any alteration in the function of mitochondria may induce changes in peroxisomal physiology. The objective of this paper was to highlight the interconnection and the crosstalk existing between mitochondria and peroxisomes. Special emphasis was placed on the best known connections between these organelles: origin, structure, and metabolic interconnections. PMID:26629313

  1. Signaling dynamics and peroxisomes.

    PubMed

    Mast, Fred D; Rachubinski, Richard A; Aitchison, John D

    2015-08-01

    Peroxisomes are remarkably responsive organelles. Their composition, abundance and even their mechanism of biogenesis are influenced strongly by cell type and the environment. This plasticity underlies peroxisomal functions in metabolism and the detoxification of dangerous reactive oxygen species. However, peroxisomes are integrated into the cellular system as a whole such that they communicate intimately with other organelles, control signaling dynamics as in the case of innate immune responses to infectious disease, and contribute to processes as fundamental as longevity. The increasing evidence for peroxisomes having roles in various cellular and organismal functions, combined with their malleability, suggests complex mechanisms operate to control cellular dynamics and the specificity of cellular responses and functions extending well beyond the peroxisome itself. A deeper understanding of the functions of peroxisomes and the mechanisms that control their plasticity could offer opportunities for exploiting changes in peroxisome abundance to control cellular function.

  2. Signaling dynamics and peroxisomes

    PubMed Central

    Mast, Fred D; Rachubinski, Richard A; Aitchison, John D

    2015-01-01

    Peroxisomes are remarkably responsive organelles. Their composition, abundance and even their mechanism of biogenesis are influenced strongly by cell type and the environment. This plasticity underlies peroxisomal functions in metabolism and the detoxification of dangerous reactive oxygen species. However, peroxisomes are integrated into the cellular system as a whole such that they communicate intimately with other organelles, control signaling dynamics as in the case of innate immune responses to infectious disease, and contribute to processes as fundamental as longevity. The increasing evidence for peroxisomes having roles in various cellular and organismal functions, combined with their malleability, suggests complex mechanisms operate to control cellular dynamics and the specificity of cellular responses and functions extending well beyond the peroxisome itself. A deeper understanding of the functions of peroxisomes and the mechanisms that control their plasticity could offer opportunities for exploiting changes in peroxisome abundance to control cellular function. PMID:26042681

  3. Highly Oxidized Peroxisomes Are Selectively Degraded via Autophagy in Arabidopsis[C][W

    PubMed Central

    Shibata, Michitaro; Oikawa, Kazusato; Yoshimoto, Kohki; Kondo, Maki; Mano, Shoji; Yamada, Kenji; Hayashi, Makoto; Sakamoto, Wataru; Ohsumi, Yoshinori; Nishimura, Mikio

    2013-01-01

    The positioning of peroxisomes in a cell is a regulated process that is closely associated with their functions. Using this feature of the peroxisomal positioning as a criterion, we identified three Arabidopsis thaliana mutants (peroxisome unusual positioning1 [peup1], peup2, and peup4) that contain aggregated peroxisomes. We found that the PEUP1, PEUP2, and PEUP4 were identical to Autophagy-related2 (ATG2), ATG18a, and ATG7, respectively, which are involved in the autophagic system. The number of peroxisomes was increased and the peroxisomal proteins were highly accumulated in the peup1 mutant, suggesting that peroxisome degradation by autophagy (pexophagy) is deficient in the peup1 mutant. These aggregated peroxisomes contained high levels of inactive catalase and were more oxidative than those of the wild type, indicating that peroxisome aggregates comprise damaged peroxisomes. In addition, peroxisome aggregation was induced in wild-type plants by exogenous application of hydrogen peroxide. The cat2 mutant also contained peroxisome aggregates. These findings demonstrate that hydrogen peroxide as a result of catalase inactivation is the inducer of peroxisome aggregation. Furthermore, an autophagosome marker, ATG8, frequently colocalized with peroxisome aggregates, indicating that peroxisomes damaged by hydrogen peroxide are selectively degraded by autophagy in the wild type. Our data provide evidence that autophagy is crucial for quality control mechanisms for peroxisomes in Arabidopsis. PMID:24368788

  4. Transient complex peroxisomal interactions

    PubMed Central

    Bonekamp, Nina A.; Schrader, Michael

    2012-01-01

    Mitochondria and peroxisomes are ubiquitous subcellular organelles that fulfill essential metabolic functions, rendering them indispensable for human development and health. Both are highly dynamic organelles that can undergo remarkable changes in morphology and number to accomplish cellular needs. While mitochondrial dynamics are also regulated by frequent fusion events, the fusion of mature peroxisomes in mammalian cells remained a matter of debate. In our recent study, we clarified systematically that there is no complete fusion of mature peroxisomes analogous to mitochondria. Moreover, in contrast to key division components such as DLP1, Fis1 or Mff, mitochondrial fusion proteins were not localized to peroxisomes. However, we discovered and characterized novel transient, complex interactions between individual peroxisomes which may contribute to the homogenization of the often heterogeneous peroxisomal compartment, e.g., by distribution of metabolites, signals or other “molecular information” via interperoxisomal contact sites. PMID:23336019

  5. [BRAF Inhibitor-Induced Erythema Nodosum-Like Lesions].

    PubMed

    Shiba, Keiko; Moriuchi, Reine; Morita, Yusuke; Nakamura, Michio; Takigami, Masayoshi; Shimizu, Satoko

    2016-05-01

    BRAF inhibitors have been licensed for the treatment of unresectable or metastatic BRAF-mutated melanomas. In Japan, the BRAF inhibitor vemurafenib has been available since December 2014. Several adverse events induced by BRAF inhibitors have been reported, such as Stevens-Johnson syndrome, toxic epidermal necrosis, squamous cell carcinoma, secondary melanoma, and hand-foot syndrome. Recently, inflammatory skin lesions clinically resembling erythema nodosum have been reported as side effects that may lead to treatment discontinuation. In this report, we described the first Japanese case of erythema nodosum-like lesions induced by vemurafenib and discussed the countermeasures to this adverse reaction. Dose reduction or interruption of BRAF inhibitors should be considered on a case-by-case basis because the condition may resolve spontaneously or under symptomatic treatment. We postulate that erythema nodosum-like lesions can be controlled by careful follow-up and supportive care. PMID:27210102

  6. Peroxisome Biogenesis and Function

    PubMed Central

    Kaur, Navneet; Reumann, Sigrun; Hu, Jianping

    2009-01-01

    Peroxisomes are small and single membrane-delimited organelles that execute numerous metabolic reactions and have pivotal roles in plant growth and development. In recent years, forward and reverse genetic studies along with biochemical and cell biological analyses in Arabidopsis have enabled researchers to identify many peroxisome proteins and elucidate their functions. This review focuses on the advances in our understanding of peroxisome biogenesis and metabolism, and further explores the contribution of large-scale analysis, such as in sillco predictions and proteomics, in augmenting our knowledge of peroxisome function In Arabidopsis. PMID:22303249

  7. Wogonin prevents lipopolysaccharide-induced acute lung injury and inflammation in mice via peroxisome proliferator-activated receptor gamma-mediated attenuation of the nuclear factor-kappaB pathway.

    PubMed

    Yao, Jing; Pan, Di; Zhao, Yue; Zhao, Li; Sun, Jie; Wang, Yu; You, Qi-Dong; Xi, Tao; Guo, Qing-Long; Lu, Na

    2014-10-01

    Acute lung injury (ALI) from a variety of clinical disorders, characterized by diffuse inflammation, is a cause of acute respiratory failure that develops in patients of all ages. Previous studies reported that wogonin, a flavonoid-like chemical compound which was found in Scutellaria baicalensis, has anti-inflammatory effects in several inflammation models, but not in ALI. Here, the in vivo protective effect of wogonin in the amelioration of lipopolysaccharide (LPS) -induced lung injury and inflammation was assessed. In addition, the in vitro effects and mechanisms of wogonin were studied in the mouse macrophage cell lines Ana-1 and RAW264.7. In vivo results indicated that wogonin attenuated LPS-induced histological alterations. Peripheral blood leucocytes decreased in the LPS-induced group, which was ameliorated by wogonin. In addition, wogonin inhibited the production of several inflammatory cytokines, including tumour necrosis factor-α, interleukin-1β (IL-1β) and IL-6, in the bronchoalveolar lavage fluid and lung tissues after LPS challenge, while the peroxisome proliferator-activated receptor γ (PPARγ) inhibitor GW9662 reversed these effects. In vitro results indicated that wogonin significantly decreased the secretion of IL-6, IL-1β and tumour necrosis factor-α in Ana-1 and RAW264.7 cells, which was suppressed by transfection of PPARγ small interfering RNA and GW9662 treatment. Moreover, wogonin activated PPARγ, induced PPARγ-mediated attenuation of the nuclear translocation and the DNA-binding activity of nuclear factor-κB in vivo and in vitro. In conclusion, all of these results showed that wogonin may serve as a promising agent for the attenuation of ALI-associated inflammation and pathology by regulating the PPARγ-involved nuclear factor-κB pathway. PMID:24766487

  8. Potentially lethal ACE-inhibitor-induced angioedema in a child.

    PubMed

    Bukhari, Esraa; Safdar, Osama Y; Shalaby, Mohammed; AlSharif, Shafiqa Mj; Alsufiany, Khoulod; Kari, Jameela A

    2015-06-01

    We report a case of a 9-year-old female with known end-stage kidney disease who presented with sudden onset tongue swelling. A diagnosis of angiotensin-converting enzyme inhibitor-induced angioedema related to bradykinin accumulation was made. Her symptoms resolved shortly after discontinuation of captopril. Early diagnosis can save patients from severe upper airway obstruction.

  9. Expression regulation and targeting of the peroxisome proliferator-activated receptor γ following electrically-induced status epilepticus.

    PubMed

    Boes, Katharina; Russmann, Vera; Ongerth, Tanja; Licko, Thomas; Salvamoser, Josephine D; Siegl, Claudia; Potschka, Heidrun

    2015-09-14

    The neuroprotective and anti-inflammatory effects of the peroxisome proliferator-activated receptor γ (PPARγ) agonist rosiglitazone are of particular interest for disease-modifying and antiepileptogenic approaches. We studied the expression of PPARγ and the impact of rosiglitazone on the consequences of status epilepticus (SE) in a rat post-SE model. Immunohistochemical analysis revealed a selective overexpression of PPARγ in the piriform cortex of rats with spontaneous seizures. Rosiglitazone administration initiated following SE failed to exert relevant effects on the development of spontaneous seizures and neuronal cell loss. Whereas spatial learning in the Morris water maze was delayed in SE animals with vehicle administration, the learning curve of rosiglitazone-treated SE rats showed no significant difference to that of controls. The study provides first evidence arguing against a robust antiepileptogenic effect. However, the findings in the spatial learning paradigm indicate disease-modifying effects. PMID:26259695

  10. Human peroxisomal disorders.

    PubMed

    Depreter, Marianne; Espeel, Marc; Roels, Frank

    2003-06-01

    Peroxisomes are single membrane-bound cell organelles performing numerous metabolic functions. The present article aims to give an overview of our current knowledge about inherited peroxisomal disorders in which these organelles are lacking or one or more of their functions are impaired. They are multiorgan disorders and the nervous system is implicated in most. After a summary of the historical names and categories, each having distinct symptoms and prognosis, microscopic pathology is reviewed in detail. Data from the literature are added to experience in the authors' laboratory with 167 liver biopsy and autopsy samples from peroxisomal patients, and with a smaller number of chorion samples for prenatal diagnosis, adrenal-, kidney-, and brain samples. Various light and electron microscopic methods are used including enzyme- and immunocytochemistry, polarizing microscopy, and morphometry. Together with other laboratory investigations and clinical data, this approach continues to contribute to the diagnosis and further characterization of peroxisomal disorders, and the discovery of novel variants. When liver specimens are examined, three main groups including 9 novel variants (33 patients) are distinguished: (1) absence or (2) presence of peroxisomes, and (3) mosaic distribution of cells with and without peroxisomes (10 patients). Renal microcysts, polarizing trilamellar inclusions, and insoluble lipid in macrophages in liver, adrenal cortex, brain, and in interstitial cells of kidney are also valuable for classification. On a genetic basis, complementation of fibroblasts has classified peroxisome biogenesis disorders into 12 complementation groups. Peroxisome biogenesis genes (PEX), knock-out-mice, and induction of redundant genes are briefly reviewed, including some recent results with 4-phenylbutyrate. Finally, regulation of peroxisome expression during development and in cell cultures, and by physiological factors is discussed. PMID:12740827

  11. Hypoxia inducible factor pathway inhibitors as anticancer therapeutics

    PubMed Central

    Burroughs, Sarah K; Kaluz, Stefan; Wang, Danzhu; Wang, Ke

    2013-01-01

    Hypoxia is a significant feature of solid tumor cancers. Hypoxia leads to a more malignant phenotype that is resistant to chemotherapy and radiation, is more invasive and has greater metastatic potential. Hypoxia activates the hypoxia inducible factor (HIF) pathway, which mediates the biological effects of hypoxia in tissues. The HIF complex acts as a transcription factor for many genes that increase tumor survival and proliferation. To date, many HIF pathway inhibitors indirectly affect HIF but there have been no clinically approved direct HIF inhibitors. This can be attributed to the complexity of the HIF pathway, as well as to the challenges of inhibiting protein–protein interactions. PMID:23573973

  12. Danhong inhibits oxidized low-density lipoprotein-induced immune maturation of dentritic cells via a peroxisome proliferator activated receptor γ-mediated pathway.

    PubMed

    Liu, Hongying; Wang, Shijun; Sun, Aijun; Huang, Dong; Wang, Wei; Zhang, Chunyu; Shi, Dazhuo; Chen, Keji; Zou, Yunzeng; Ge, Junbo

    2012-01-01

    Danhong injection (DHI), a Chinese Materia Medica standardized product extracted from Radix Salviae miltiorrhizae and Flos Carthami tinctorii, is effective in the treatment of atherosclerosis (AS)-related diseases. It is widely recognized that AS is a complex inflammatory disease of the arterial wall and the dendritic cells (DCs) is a major player in the pathogenesis of AS via mediating atherosclerotic antigen presenting and T lymphocytes. Here, we determined the effect and possible mechanism of DHI on oxidized low-density lipoprotein (ox-LDL)-induced maturation and immune function of DCs. Human monocyte-derived DCs were incubated with DHI or ciglitazone and were subsequently stimulated with ox-LDL to induce maturation. Similar to ciglitazone, a peroxisome proliferator activated receptor (PPAR) γ agonist, DHI, could significantly reduce ox-LDL-induced expressions of mature markers, enhance the endocytotic function, and inhibit secretions of cytokine on DCs. These effects of DHI could be partly reversed by silencing the PPARγ. In conclusion, DHI could inhibit ox-LDL-induced maturation of DCs partly through activating a PPARγ-mediated signaling pathway.

  13. Peroxisome proliferator-activated receptor δ (PPARδ) induces estrogen receptor-positive mammary neoplasia through an inflammatory and metabolic phenotype linked to mTor activation

    PubMed Central

    Yuan, Hongyan; Lu, Jin; Xiao, Junfeng; Upadhyay, Geeta; Umans, Rachel; Kallakury, Bhaskar; Yin, Yuhzi; Fant, Michael E.; Kopelovich, Levy; Glazer, Robert I.

    2013-01-01

    The peroxisome proliferator-activated receptor-δ (PPARδ) regulates a multitude of physiological processes associated with glucose and lipid metabolism, inflammation and proliferation. One or more of these processes are potential risk factors for the ability of PPARδ agonists to promote tumorigenesis in the mammary gland. In the present study, we describe a new transgenic mouse model in which activation of PPARδ in the mammary epithelium by endogenous or synthetic ligands resulted in progressive histopathological changes that culminated in the appearance of estrogen receptor- and progesterone receptor-positive and ErbB2-negative infiltrating ductal carcinomas. Multiparous mice presented with mammary carcinomas after a latency of 12 months, and administration of the PPARδ ligand GW501516 reduced tumor latency to five months. Histopathological changes occurred concurrently with an increase in an inflammatory, invasive, metabolic and proliferative gene signature, including expression of the trophoblast gene, Plac1, beginning one week after GW501516 treatment, and remained elevated throughout tumorigenesis. The appearance of malignant changes correlated with a pronounced increase in phosphatidylcholine and lysophosphatidic acid metabolites, which coincided with activation of Akt and mTor signaling that were attenuated by treatment with the mTor inhibitor everolimus. Our findings are the first to demonstrate a direct role of PPARδ in the pathogenesis of mammary tumorigenesis, and suggest a rationale for therapeutic approaches to prevent and treat this disease. PMID:23811944

  14. Activation of peroxisome proliferator-activated receptor-{gamma} (PPAR{gamma}) induces cell death through MAPK-dependent mechanism in osteoblastic cells

    SciTech Connect

    Kim, Sung Hun; Yoo, Chong Il; Kim, Hui Taek; Park, Ji Yeon; Kwon, Chae Hwa; Keun Kim, Yong . E-mail: kim430@pusan.ac.kr

    2006-09-01

    The present study was undertaken to determine the role of the mitogen-activated protein kinase (MAPK) subfamilies in cell death induced by PPAR{gamma} agonists in osteoblastic cells. Ciglitazone and troglitazone, PPAR{gamma} agonists, resulted in a concentration- and time-dependent cell death, which was largely attributed to apoptosis. But a PPAR{alpha} agonist ciprofibrate did not affect the cell death. Ciglitazone caused reactive oxygen species (ROS) generation and ciglitazone-induced cell death was prevented by antioxidants, suggesting an important role of ROS generation in the ciglitazone-induced cell death. ROS generation and cell death induced by ciglitazone were inhibited by the PPAR{gamma} antagonist GW9662. Ciglitazone treatment caused activation of extracellular signal-regulated kinase (ERK) and p38. Activation of ERK was dependent on epidermal growth factor receptor (EGFR) and that of p38 was independent. Ciglitazone-induced cell death was significantly prevented by PD98059, an inhibitor of ERK upstream kinase MEK1/2, and SB203580, a p38 inhibitor. Ciglitazone treatment increased Bax expression and caused a loss of mitochondrial membrane potential, and its effect was prevented by N-acetylcysteine, PD98059, and SB203580. Ciglitazone induced caspase activation, which was prevented by PD98059 and SB203580. The general caspase inhibitor z-DEVD-FMK and the specific inhibitor of caspases-3 DEVD-CHO exerted the protective effect against the ciglitazone-induced cell death. The EGFR inhibitors AG1478 and suramin protected against the ciglitazone-induced cell death. Taken together, these findings suggest that the MAPK signaling pathways play an active role in mediating the ciglitazone-induced cell death of osteoblasts and function upstream of a mitochondria-dependent mechanism. These data may provide a novel insight into potential therapeutic strategies for treatment of osteoporosis.

  15. Peroxisomes take shape

    PubMed Central

    Smith, Jennifer J.; Aitchison, John D.

    2014-01-01

    Peroxisomes carry out various oxidative reactions that are tightly regulated to adapt to the changing needs of the cell and varying external environments. Accordingly, they are remarkably fluid and can change dramatically in abundance, size, shape and content in response to numerous cues. These dynamics are controlled by multiple aspects of peroxisome biogenesis that are coordinately regulated with each other and with other cellular processes. Ongoing studies are deciphering the diverse molecular mechanisms that underlie biogenesis and how they cooperate to dynamically control peroxisome utility. These important challenges should lead to an understanding of peroxisome dynamics that can be capitalized upon for bioengineering and the development of therapies to improve human health. PMID:24263361

  16. Isorhamnetin Inhibits Proliferation and Invasion and Induces Apoptosis through the Modulation of Peroxisome Proliferator-activated Receptor γ Activation Pathway in Gastric Cancer*

    PubMed Central

    Ramachandran, Lalitha; Manu, Kanjoormana Aryan; Shanmugam, Muthu K.; Li, Feng; Siveen, Kodappully Sivaraman; Vali, Shireen; Kapoor, Shweta; Abbasi, Taher; Surana, Rohit; Smoot, Duane T.; Ashktorab, Hassan; Tan, Patrick; Ahn, Kwang Seok; Yap, Chun Wei; Kumar, Alan Prem; Sethi, Gautam

    2012-01-01

    Gastric cancer (GC) is a lethal malignancy and the second most common cause of cancer-related deaths. Although treatment options such as chemotherapy, radiotherapy, and surgery have led to a decline in the mortality rate due to GC, chemoresistance remains as one of the major causes for poor prognosis and high recurrence rate. In this study, we investigated the potential effects of isorhamnetin (IH), a 3′-O-methylated metabolite of quercetin on the peroxisome proliferator-activated receptor γ (PPAR-γ) signaling cascade using proteomics technology platform, GC cell lines, and xenograft mice model. We observed that IH exerted a strong antiproliferative effect and increased cytotoxicity in combination with chemotherapeutic drugs. IH also inhibited the migratory/invasive properties of GC cells, which could be reversed in the presence of PPAR-γ inhibitor. We found that IH increased PPAR-γ activity and modulated the expression of PPAR-γ regulated genes in GC cells. Also, the increase in PPAR-γ activity was reversed in the presence of PPAR-γ-specific inhibitor and a mutated PPAR-γ dominant negative plasmid, supporting our hypothesis that IH can act as a ligand of PPAR-γ. Using molecular docking analysis, we demonstrate that IH formed interactions with seven polar residues and six nonpolar residues within the ligand-binding pocket of PPAR-γ that are reported to be critical for its activity and could competitively bind to PPAR-γ. IH significantly increased the expression of PPAR-γ in tumor tissues obtained from xenograft model of GC. Overall, our findings clearly indicate that antitumor effects of IH may be mediated through modulation of the PPAR-γ activation pathway in GC. PMID:22992727

  17. Rosiglitazone prevents advanced glycation end products-induced renal toxicity likely through suppression of plasminogen activator inhibitor-1.

    PubMed

    Yu, Xiaoyan; Li, Cai; Li, Xiaokun; Cai, Lu

    2007-04-01

    In the development of diabetic nephropathy, advanced glycation end products (AGEs) play a causative role via induction of extracellular matrix (ECM) accumulation. Plasminogen activator inhibitor-1 (PAI-1), as a major inhibitor of plasminogen activator that plays an important role in degrading ECM, was found to significantly increase in renal fibrotic diseases. Activation of peroxisome proliferator-activated receptor (PPAR)-gamma prevented diabetic nephropathy. The present study, therefore, was to define whether or not AGE-induced renal ECM accumulation and renal dysfunction are mediated by upregulation of PAI-1 expression and whether or not PPAR-gamma agonist can attenuate these AGE effects via suppressing PAI-1 expression. Rats were given AGEs alone by iv injection at 100 mg/kg daily with or without oral supplementation of PPAR-gamma agonist rosiglitazone (RGZ) at 2 mg/kg daily for 6 weeks. Results showed that AGEs induced a renal ECM accumulation, as shown by increases in periodic acid-Schiff-positive materials, fibronectin, and type IV collagen (Col IV) contents in glomeruli, and a mild renal dysfunction, as shown by an increase in urinary proteins. AGEs also caused an increase in PAI-1 expression and a decrease in plasminogen activator bioactivity in the kidney. Treatment with RGZ significantly ameliorated AGE-induced renal ECM accumulation, proteinuria, and PAI-1 upregulation. Direct exposure of rat mesangial cells to AGEs in vitro induced increases in fibronectin and Col IV syntheses along with an increase in PAI-1 expression, effects significantly attenuated by RGZ. Preincubation of PAI-1 antibody to AGE-treated mesangial cells completely prevented AGE-induced fibronectin and Col IV production. These results suggest that upregulation of PAI-1 expression plays a critical role in AGE-induced renal ECM accumulation. Renal protection of RGZ from AGEs may be associated with the suppression of PAI-1 expression through PPAR-dependent and independent mechanisms.

  18. Constitutive active/androstane receptor, peroxisome proliferator-activated receptor α, and cytotoxicity are involved in oxadiazon-induced liver tumor development in mice.

    PubMed

    Kuwata, Kazunori; Inoue, Kaoru; Ichimura, Ryohei; Takahashi, Miwa; Kodama, Yukio; Yoshida, Midori

    2016-02-01

    Oxadiazon (OX) is a protoporphyrinogen oxidase-inhibiting herbicide that induces porphyria and liver tumors in rodents. Although porphyria is generally considered to be a risk factor for liver tumor development, the mechanisms through which OX mediates tumor development are unclear. Therefore, in this study, we investigated the mechanisms of tumor development by focusing on constitutive active/androstane receptor (CAR), which is essential for the development of tumors in response to several chemicals. After 1, 4, or 13 weeks of dietary treatment with 1000 ppm OX, hepatic Cyp2b10 expression was induced in wild-type (WT) mice. However, this effect was blocked in CAR-knockout (CARKO) mice. Hepatic Cyp4a10 expression, indicative of peroxisome proliferator-activated receptor α (PPARα) activation, and cytotoxic changes in hepatocytes were also observed in both groups of mice. After initiation by diethylnitrosamine, 26-week treatment with OX resulted in an increase in proliferative lesions, including foci and adenomas, in both genotypes, and the incidence and multiplicity of proliferative lesions in CARKO mice were higher than those in control mice but lower than those in WT mice. These results suggested that CAR, PPARα activation, and cytotoxicity were involved in the development of liver tumors. Moreover, porphyrin was not apparently involved in OX-induced tumor development.

  19. Ginger extract prevents high-fat diet-induced obesity in mice via activation of the peroxisome proliferator-activated receptor δ pathway.

    PubMed

    Misawa, Koichi; Hashizume, Kojiro; Yamamoto, Masaki; Minegishi, Yoshihiko; Hase, Tadashi; Shimotoyodome, Akira

    2015-10-01

    The initiation of obesity entails an imbalance wherein energy intake exceeds expenditure. Obesity is increasing in prevalence and is now a worldwide health problem. Food-derived peroxisome proliferator-activated receptor δ (PPARδ) stimulators represent potential treatment options for obesity. Ginger (Zingiber officinale Roscoe) was previously shown to regulate the PPARγ signaling pathway in adipocytes. In this study, we investigated the antiobesity effects of ginger in vivo and the mechanism of action in vitro. Energy expenditure was increased, and diet-induced obesity was attenuated in C57BL/6J mice treated with dietary ginger extract (GE). GE also increased the number of Type I muscle fibers, improved running endurance capacity and upregulated PPARδ-targeted gene expression in skeletal muscle and the liver. 6-Shogaol and 6-gingerol acted as specific PPARδ ligands and stimulated PPARδ-dependent gene expression in cultured human skeletal muscle myotubes. An analysis of cellular respiration revealed that pretreating cultured skeletal muscle myotubes with GE increased palmitate-induced oxygen consumption rate, which suggested an increase in cellular fatty acid catabolism. These results demonstrated that sustained activation of the PPARδ pathway with GE attenuated diet-induced obesity and improved exercise endurance capacity by increasing skeletal muscle fat catabolism. 6-Shogaol and 6-gingerol may be responsible for the regulatory effects of dietary ginger on PPARδ signaling. PMID:26101135

  20. Ligands for peroxisome proliferator-activated receptors alpha and gamma inhibit chemically induced colitis and formation of aberrant crypt foci in rats.

    PubMed

    Tanaka, T; Kohno, H; Yoshitani, S; Takashima, S; Okumura, A; Murakami, A; Hosokawa, M

    2001-03-15

    The biological role of the peroxisome proliferator-activated receptors (PPARs) in various diseases, including inflammation and cancer, has been highlighted recently. Although PPARgamma ligands have been found to inhibit mammary carcinogenesis in rodents, the effects on colon tumorigenesis are controversial. In the present study, three different experiments were conducted to investigate the modifying effects of PPARs ligands (PPARalpha and PPARgamma) on colitis and an early phase of colitis-related colon carcinogenesis in male F344 rats. In the first experiment, gastric gavage of troglitazone (PPARgamma ligand, 10 or 100 mg/kg body weight) or bezafibrate (PPARalpha ligand, 10 or 100 mg/kg body weight) inhibited colitis induced by dextran sodium sulfate (DSS) and lowered trefoil factor-2 content in colonic mucosa. In the second experiment, dietary administration (0.01 or 0.05% in diet) of troglitazone and bezafibrate for 4 weeks significantly reduced azoxymethane (AOM, two weekly s.c. injections, 20 mg/kg body weight)-induced formation of aberrant crypts foci, which are precursor lesions for colon carcinoma. In the third experiment, dietary administration (0.01% in diet for 6 weeks) of pioglitazone (PPARgamma ligand), troglitazone, and bezafibrate effectively suppressed DSS/AOM-induced ACF. Administration of both ligands significantly reduced cell proliferation activity in colonic mucosa exposed to DSS and AOM. Our results suggest that synthetic PPARs ligands (PPARalpha and PPARgamma) can inhibit the early stages of colon tumorigenesis with or without colitis.

  1. Administration of the peroxisomal proliferator-activated receptor {gamma} agonist pioglitazone during fractionated brain irradiation prevents radiation-induced cognitive impairment

    SciTech Connect

    Zhao Weiling; Payne, Valerie; Tommasi, Ellen; Diz, Debra I.; Hsu, F.-C.; Robbins, Mike E. . E-mail: mrobbins@wfubmc.edu

    2007-01-01

    Purpose: We hypothesized that administration of the anti-inflammatory peroxisomal proliferator-activated receptor {gamma} (PPAR{gamma}) agonist pioglitazone (Pio) to adult male rats would inhibit radiation-induced cognitive impairment. Methods and Materials: Young adult male F344 rats received one of the following: (1) fractionated whole brain irradiation (WBI); 40 or 45 Gy {gamma}-rays in 4 or 4.5 weeks, respectively, two fractions per week and normal diet; (2) sham-irradiation and normal diet; (3) WBI plus Pio (120 ppm) before, during, and for 4 or 54 weeks postirradiation; (4) sham-irradiation plus Pio; or (5) WBI plus Pio starting 24h after completion of WBI. Results: Administration of Pio before, during, and for 4 or 54 weeks after WBI prevented Radiation-induced cognitive impairment. Administration of Pio for 54 weeks starting after completion of fractionated WBI substantially but not significantly reduced Radiation-induced cognitive impairment. Conclusions: These findings offer the promise of improving the quality of life and increasing the therapeutic window for brain tumor patients.

  2. Ginger extract prevents high-fat diet-induced obesity in mice via activation of the peroxisome proliferator-activated receptor δ pathway.

    PubMed

    Misawa, Koichi; Hashizume, Kojiro; Yamamoto, Masaki; Minegishi, Yoshihiko; Hase, Tadashi; Shimotoyodome, Akira

    2015-10-01

    The initiation of obesity entails an imbalance wherein energy intake exceeds expenditure. Obesity is increasing in prevalence and is now a worldwide health problem. Food-derived peroxisome proliferator-activated receptor δ (PPARδ) stimulators represent potential treatment options for obesity. Ginger (Zingiber officinale Roscoe) was previously shown to regulate the PPARγ signaling pathway in adipocytes. In this study, we investigated the antiobesity effects of ginger in vivo and the mechanism of action in vitro. Energy expenditure was increased, and diet-induced obesity was attenuated in C57BL/6J mice treated with dietary ginger extract (GE). GE also increased the number of Type I muscle fibers, improved running endurance capacity and upregulated PPARδ-targeted gene expression in skeletal muscle and the liver. 6-Shogaol and 6-gingerol acted as specific PPARδ ligands and stimulated PPARδ-dependent gene expression in cultured human skeletal muscle myotubes. An analysis of cellular respiration revealed that pretreating cultured skeletal muscle myotubes with GE increased palmitate-induced oxygen consumption rate, which suggested an increase in cellular fatty acid catabolism. These results demonstrated that sustained activation of the PPARδ pathway with GE attenuated diet-induced obesity and improved exercise endurance capacity by increasing skeletal muscle fat catabolism. 6-Shogaol and 6-gingerol may be responsible for the regulatory effects of dietary ginger on PPARδ signaling.

  3. Hypoxia and reoxygenation of primary human hepatocytes induce proteome changes of glucose metabolism, oxidative protection and peroxisomal function.

    PubMed

    Strey, Christoph W; Gestrich, Johannes; Beckhaus, Tobias; Marquez-Pinilla, Rosa Maria; Oppermann, Elsie; Mönch, Christian; Lambris, John D; Karas, Michael; Bechstein, Wolf O

    2010-10-01

    Protective hepatocellular responses to a hypoxic challenge are crucial to preserve liver function. The knowledge of affected metabolic functions could help assess and enhance hepatic ischemic tolerance. Here we studied adaptive mechanisms in human hepatocytes after hypoxia and reoxygenation using a proteomic approach. Proteins from primary hepatocytes were extracted after 6 h of hypoxia and 24 h of reoxygenation. The proteome was analyzed by 2D-electrophoresis. Densitometry and mass spectrometry (MALDI-TOF-MS) were used for protein identification. Two hundred and sixty-two spots were differentially analyzed and 33 spots displayed significant differences between hypoxic and normoxic cells. Seventeen proteins were identified by mass spectrometry. After hypoxia and reoxygenation the UTP-glucose-1-phosphate uridyltransferase, phosphoglycerate kinase1, fructose-1,6-bisphosphate aldolase, glyceraldehyde-3-phosphate dehydrogenase, fructose-1,6-bisphosphatase, thiosulfat-sulfurtransferase, thioredoxin peroxidase, peroxiredoxin III, and annexin A2 proteins were down-regulated. An increased expression was found for carbamoyl phosphate synthetase I, heat shock 70 kDa protein5, phosphoenolpyruvate carboxy-kinase, catalase isoform2, peroxiredoxin II, glutathione S-transferase, hydroxyacid oxidase1, and F1-ATP synthase, alpha subunit1. Hepatocellular adaptation to hypoxia and reoxygenation involve glucose metabolism, peroxisomal functions, and oxidative stress protection. The identified proteins can serve as possible diagnostic targets to monitor hepatic hypoxic tolerance e.g. in the context of liver surgery and transplantation.

  4. Plant Peroxisomes: Biogenesis and Function

    PubMed Central

    Hu, Jianping; Baker, Alison; Bartel, Bonnie; Linka, Nicole; Mullen, Robert T.; Reumann, Sigrun; Zolman, Bethany K.

    2012-01-01

    Peroxisomes are eukaryotic organelles that are highly dynamic both in morphology and metabolism. Plant peroxisomes are involved in numerous processes, including primary and secondary metabolism, development, and responses to abiotic and biotic stresses. Considerable progress has been made in the identification of factors involved in peroxisomal biogenesis, revealing mechanisms that are both shared with and diverged from non-plant systems. Furthermore, recent advances have begun to reveal an unexpectedly large plant peroxisomal proteome and have increased our understanding of metabolic pathways in peroxisomes. Coordination of the biosynthesis, import, biochemical activity, and degradation of peroxisomal proteins allows for highly dynamic responses of peroxisomal metabolism to meet the needs of a plant. Knowledge gained from plant peroxisomal research will be instrumental to fully understanding the organelle’s dynamic behavior and defining peroxisomal metabolic networks, thus allowing the development of molecular strategies for rational engineering of plant metabolism, biomass production, stress tolerance, and pathogen defense. PMID:22669882

  5. Potentially lethal ACE-inhibitor-induced angioedema in a child

    PubMed Central

    Bukhari, Esraa; Safdar, Osama Y; Shalaby, Mohammed; AlSharif, Shafiqa MJ; Alsufiany, Khoulod; Kari, Jameela A

    2015-01-01

    Key Clinical Message We report a case of a 9-year-old female with known end-stage kidney disease who presented with sudden onset tongue swelling. A diagnosis of angiotensin-converting enzyme inhibitor-induced angioedema related to bradykinin accumulation was made. Her symptoms resolved shortly after discontinuation of captopril. Early diagnosis can save patients from severe upper airway obstruction. PMID:26185642

  6. PEROXISOME PROLIFERATOR-ACTIVATED RECEPTORα (PPARα) AGONISTS DIFFERENTIALLY REGULATE INHIBITOR OF DNA BINDING (ID2) EXPRESSION IN RODENTS AND HUMAN CELLS

    EPA Science Inventory

    Abstract Inhibitor of DNA binding (Id2) is a member of the helix-loop-helix (HLH) transcription factor family whose members play important roles in cell differentiation and proliferation. Id2 has been linked to the development of cardiovascular diseases since thiazolidinediones,...

  7. Histone deacetylase inhibitors induce autophagy through FOXO1-dependent pathways.

    PubMed

    Zhang, Jianbin; Ng, Shukie; Wang, Jigang; Zhou, Jing; Tan, Shi-Hao; Yang, Naidi; Lin, Qingsong; Xia, Dajing; Shen, Han-Ming

    2015-04-01

    Autophagy is a catabolic process in response to starvation or other stress conditions to sustain cellular homeostasis. At present, histone deacetylase inhibitors (HDACIs) are known to induce autophagy in cells through inhibition of mechanistic target of rapamycin (MTOR) pathway. FOXO1, an important transcription factor regulated by AKT, is also known to play a role in autophagy induction. At present, the role of FOXO1 in the HDACIs-induced autophagy has not been reported. In this study, we first observed that HDACIs increased the expression of FOXO1 at the mRNA and protein level. Second, we found that FOXO1 transcriptional activity was enhanced by HDACIs, as evidenced by increased FOXO1 nuclear accumulation and transcriptional activity. Third, suppression of FOXO1 function by siRNA knockdown or by a chemical inhibitor markedly blocked HDACIs-induced autophagy. Moreover, we found that FOXO1-mediated autophagy is achieved via its transcriptional activation, leading to a dual effect on autophagy induction: (i) enhanced expression of autophagy-related (ATG) genes, and (ii) suppression of MTOR via transcription of the SESN3 (sestrin 3) gene. Finally, we found that inhibition of autophagy markedly enhanced HDACIs-mediated cell death, indicating that autophagy serves as an important cell survival mechanism. Taken together, our studies reveal a novel function of FOXO1 in HDACIs-mediated autophagy in human cancer cells and thus support the development of a novel therapeutic strategy by combining HDACIs and autophagy inhibitors in cancer therapy.

  8. Peroxisome proliferator-activated receptor alpha acts as a mediator of endoplasmic reticulum stress-induced hepatocyte apoptosis in acute liver failure

    PubMed Central

    Zhang, Li; Ren, Feng; Zhang, Xiangying; Wang, Xinxin; Shi, Hongbo; Zhou, Li; Zheng, Sujun; Chen, Yu; Chen, Dexi; Li, Liying; Duan, Zhongping

    2016-01-01

    ABSTRACT Peroxisome proliferator-activated receptor α (PPARα) is a key regulator to ameliorate liver injury in cases of acute liver failure (ALF). However, its regulatory mechanisms remain largely undetermined. Endoplasmic reticulum stress (ER stress) plays an important role in a number of liver diseases. This study aimed to investigate whether PPARα activation inhibits ER stress-induced hepatocyte apoptosis, thereby protecting against ALF. In a murine model of D-galactosamine (D-GalN)- and lipopolysaccharide (LPS)-induced ALF, Wy-14643 was administered to activate PPARα, and 4-phenylbutyric acid (4-PBA) was administered to attenuate ER stress. PPARα activation ameliorated liver injury, because pre-administration of its specific inducer, Wy-14643, reduced the serum aminotransferase levels and preserved liver architecture compared with that of controls. The protective effect of PPARα activation resulted from the suppression of ER stress-induced hepatocyte apoptosis. Indeed, (1) PPARα activation decreased the expression of glucose-regulated protein 78 (Grp78), Grp94 and C/EBP-homologous protein (CHOP) in vivo; (2) the liver protection by 4-PBA resulted from the induction of PPARα expression, as 4-PBA pre-treatment promoted upregulation of PPARα, and inhibition of PPARα by small interfering RNA (siRNA) treatment reversed liver protection and increased hepatocyte apoptosis; (3) in vitro PPARα activation by Wy-14643 decreased hepatocyte apoptosis induced by severe ER stress, and PPARα inhibition by siRNA treatment decreased the hepatocyte survival induced by mild ER stress. Here, we demonstrate that PPARα activation contributes to liver protection and decreases hepatocyte apoptosis in ALF, particularly through regulating ER stress. Therefore, targeting PPARα could be a potential therapeutic strategy to ameliorate ALF. PMID:27482818

  9. Peroxisome proliferator-activated receptor alpha acts as a mediator of endoplasmic reticulum stress-induced hepatocyte apoptosis in acute liver failure.

    PubMed

    Zhang, Li; Ren, Feng; Zhang, Xiangying; Wang, Xinxin; Shi, Hongbo; Zhou, Li; Zheng, Sujun; Chen, Yu; Chen, Dexi; Li, Liying; Zhao, Caiyan; Duan, Zhongping

    2016-07-01

    Peroxisome proliferator-activated receptor α (PPARα) is a key regulator to ameliorate liver injury in cases of acute liver failure (ALF). However, its regulatory mechanisms remain largely undetermined. Endoplasmic reticulum stress (ER stress) plays an important role in a number of liver diseases. This study aimed to investigate whether PPARα activation inhibits ER stress-induced hepatocyte apoptosis, thereby protecting against ALF. In a murine model of D-galactosamine (D-GalN)- and lipopolysaccharide (LPS)-induced ALF, Wy-14643 was administered to activate PPARα, and 4-phenylbutyric acid (4-PBA) was administered to attenuate ER stress. PPARα activation ameliorated liver injury, because pre-administration of its specific inducer, Wy-14643, reduced the serum aminotransferase levels and preserved liver architecture compared with that of controls. The protective effect of PPARα activation resulted from the suppression of ER stress-induced hepatocyte apoptosis. Indeed, (1) PPARα activation decreased the expression of glucose-regulated protein 78 (Grp78), Grp94 and C/EBP-homologous protein (CHOP) in vivo; (2) the liver protection by 4-PBA resulted from the induction of PPARα expression, as 4-PBA pre-treatment promoted upregulation of PPARα, and inhibition of PPARα by small interfering RNA (siRNA) treatment reversed liver protection and increased hepatocyte apoptosis; (3) in vitro PPARα activation by Wy-14643 decreased hepatocyte apoptosis induced by severe ER stress, and PPARα inhibition by siRNA treatment decreased the hepatocyte survival induced by mild ER stress. Here, we demonstrate that PPARα activation contributes to liver protection and decreases hepatocyte apoptosis in ALF, particularly through regulating ER stress. Therefore, targeting PPARα could be a potential therapeutic strategy to ameliorate ALF. PMID:27482818

  10. Novel EGFR inhibitors attenuate cardiac hypertrophy induced by angiotensin II.

    PubMed

    Peng, Kesong; Tian, Xinqiao; Qian, Yuanyuan; Skibba, Melissa; Zou, Chunpeng; Liu, Zhiguo; Wang, Jingying; Xu, Zheng; Li, Xiaokun; Liang, Guang

    2016-03-01

    Cardiac hypertrophy is an important risk factor for heart failure. Epidermal growth factor receptor (EGFR) has been found to play a role in the pathogenesis of various cardiovascular diseases. The aim of this current study was to examine the role of EGFR in angiotensin II (Ang II)-induced cardiac hypertrophy and identify the underlying molecular mechanisms. In this study, we observed that both Ang II and EGF could increase the phospohorylation of EGFR and protein kinase B (AKT)/extracellular signal-regulated kinase (ERK), and then induce cell hypertrophy in H9c2 cells. Both pharmacological inhibitors and genetic silencing significantly reduced Ang II-induced EGFR signalling pathway activation, hypertrophic marker overexpression, and cell hypertrophy. In addition, our results showed that Ang II-induced EGFR activation is mediated by c-Src phosphorylation. In vivo, Ang II treatment significantly led to cardiac remodelling including cardiac hypertrophy, disorganization and fibrosis, accompanied by the activation of EGFR signalling pathway in the heart tissues, while all these molecular and pathological alterations were attenuated by the oral administration with EGFR inhibitors. In conclusion, the c-Src-dependent EGFR activation may play an important role in Ang II-induced cardiac hypertrophy, and inhibition of EGFR by specific molecules may be an effective strategy for the treatment of Ang II-associated cardiac diseases. PMID:26762600

  11. Cell death is induced by ciglitazone, a peroxisome proliferator-activated receptor {gamma} (PPAR{gamma}) agonist, independently of PPAR{gamma} in human glioma cells

    SciTech Connect

    Lee, Myoung Woo; Kim, Dae Seong; Kim, Hye Ryung; Kim, Hye Jin; Yang, Jin Mo; Ryu, Somi; Noh, Yoo Hun; Lee, Soo Hyun; Son, Meong Hi; Jung, Hye Lim; Yoo, Keon Hee; Koo, Hong Hoe; Sung, Ki Woong

    2012-01-06

    Highlights: Black-Right-Pointing-Pointer Greater than 30 {mu}M ciglitazone induces cell death in glioma cells. Black-Right-Pointing-Pointer Cell death by ciglitazone is independent of PPAR{gamma} in glioma cells. Black-Right-Pointing-Pointer CGZ induces cell death by the loss of MMP via decreased Akt. -- Abstract: Peroxisome proliferator-activated receptor {gamma} (PPAR{gamma}) regulates multiple signaling pathways, and its agonists induce apoptosis in various cancer cells. However, their role in cell death is unclear. In this study, the relationship between ciglitazone (CGZ) and PPAR{gamma} in CGZ-induced cell death was examined. At concentrations of greater than 30 {mu}M, CGZ, a synthetic PPAR{gamma} agonist, activated caspase-3 and induced apoptosis in T98G cells. Treatment of T98G cells with less than 30 {mu}M CGZ effectively induced cell death after pretreatment with 30 {mu}M of the PPAR{gamma} antagonist GW9662, although GW9662 alone did not induce cell death. This cell death was also observed when cells were co-treated with CGZ and GW9662, but was not observed when cells were treated with CGZ prior to GW9662. In cells in which PPAR{gamma} was down-regulated cells by siRNA, lower concentrations of CGZ (<30 {mu}M) were sufficient to induce cell death, although higher concentrations of CGZ ( Greater-Than-Or-Slanted-Equal-To 30 {mu}M) were required to induce cell death in control T98G cells, indicating that CGZ effectively induces cell death in T98G cells independently of PPAR{gamma}. Treatment with GW9662 followed by CGZ resulted in a down-regulation of Akt activity and the loss of mitochondrial membrane potential (MMP), which was accompanied by a decrease in Bcl-2 expression and an increase in Bid cleavage. These data suggest that CGZ is capable of inducing apoptotic cell death independently of PPAR{gamma} in glioma cells, by down-regulating Akt activity and inducing MMP collapse.

  12. Src is activated by the nuclear receptor peroxisome proliferator-activated receptor β/δ in ultraviolet radiation-induced skin cancer.

    PubMed

    Montagner, Alexandra; Delgado, Maria B; Tallichet-Blanc, Corinne; Chan, Jeremy S K; Sng, Ming K; Mottaz, Hélén; Degueurce, Gwendoline; Lippi, Yannick; Moret, Catherine; Baruchet, Michael; Antsiferova, Maria; Werner, Sabine; Hohl, Daniel; Saati, Talal Al; Farmer, Pierre J; Tan, Nguan S; Michalik, Liliane; Wahli, Walter

    2014-01-01

    Although non-melanoma skin cancer (NMSC) is the most common human cancer and its incidence continues to rise worldwide, the mechanisms underlying its development remain incompletely understood. Here, we unveil a cascade of events involving peroxisome proliferator-activated receptor (PPAR) β/δ and the oncogene Src, which promotes the development of ultraviolet (UV)-induced skin cancer in mice. UV-induced PPARβ/δ activity, which directly stimulated Src expression, increased Src kinase activity and enhanced the EGFR/Erk1/2 signalling pathway, resulting in increased epithelial-to-mesenchymal transition (EMT) marker expression. Consistent with these observations, PPARβ/δ-null mice developed fewer and smaller skin tumours, and a PPARβ/δ antagonist prevented UV-dependent Src stimulation. Furthermore, the expression of PPARβ/δ positively correlated with the expression of SRC and EMT markers in human skin squamous cell carcinoma (SCC), and critically, linear models applied to several human epithelial cancers revealed an interaction between PPARβ/δ and SRC and TGFβ1 transcriptional levels. Taken together, these observations motivate the future evaluation of PPARβ/δ modulators to attenuate the development of several epithelial cancers. PMID:24203162

  13. Caffeic Acid Inhibits UVB-induced Inflammation and Photocarcinogenesis Through Activation of Peroxisome Proliferator-activated Receptor-γ in Mouse Skin.

    PubMed

    Balupillai, Agilan; Prasad, Rajendra N; Ramasamy, Karthikeyan; Muthusamy, Ganesan; Shanmugham, Mohana; Govindasamy, Kanimozhi; Gunaseelan, Srithar

    2015-11-01

    In this study, the effect of caffeic acid (CA) on both acute and chronic UVB-irradiation-induced inflammation and photocarcinogenesis was investigated in Swiss albino mice. Animals were exposed to 180 mJ cm(-2) of UVB once daily for 10 consecutive days and thrice weekly for 30 weeks for acute and chronic study respectively. UVB exposure for 10 consecutive days showed edema formation, increased lipid peroxidation and decreased antioxidant status with activation of inflammatory molecules such as TNF-α, IL-6, COX-2 and NF-κB. However, CA (15 mg per kg.b.wt.) administration before each UVB exposure decreased lipid peroxidation, inflammatory markers expression and enhanced antioxidant status probably through the activation of peroxisome proliferator-activated receptors (PPARγ) in the mice skin. PPARγ is considered a potential target for photochemoprevention because it inhibits UVB-mediated inflammatory responses. In this study, UVB exposure for 30 weeks caused squamous cell carcinoma and upregulation of iNOS, VEGF and TGF-β and downregulation of p53 and tumor incidence in the mice skin. Both topical (CAT) and intraperitoneal (CAIP) treatment before each UVB exposure downregulates iNOS, VEGF, TGF-β, upregulates p53 and reduces tumors multiplicity in the mice skin. Thus, CA offers protection against UVB-induced photocarcinogenesis probably through activation of anti-inflammatory transcription factor PPARγ in the mice.

  14. Hypoxia induces peroxisome proliferator-activated receptor γ expression via HIF-1-dependent mechanisms in HepG2 cell line.

    PubMed

    Zhao, Ying-Ze; Liu, Xiao-Ling; Shen, Guo-Min; Ma, Yan-Ni; Zhang, Feng-Lin; Chen, Ming-Tai; Zhao, Hua-Lu; Yu, Jia; Zhang, Jun-Wu

    2014-02-01

    Hypoxia-inducible factor-1 (HIF-1) can activate expression of a broad range of genes in response to hypoxia. It has been shown that the levels of peroxisome proliferator-activated receptor γ (PPARγ) are influenced by changes in oxygen tension, and PPARγ plays a critical role in metabolism regulation and cancers. In this research, we observed an increased PPARγ mRNA and protein levels in company with increased HIF-1 protein levels in HepG2 cells in hypoxia as compared with in normoxia. Enforced expression of HIF-1α induced PPARγ1 and PPARγ2 expression, while knockdown of HIF-1α by small interference RNA deduced PPARγ1 and PPARγ2 expression in HepG2 cells under hypoxic conditions. By dual-luciferase reporter assay and chromatin immunoprecipitation assay we confirmed a functional hypoxic response element (HRE) localized at 684bp upstream of the transcriptional start site (TSS) of PPARγ1 and a functional HRE localized at 204bp downstream of the TSS of PPARγ2 in HepG2 cells. Additionally we observed an increase and co-presence of PPARγ and HIF-1α, and a highly positive correlation between PPARγ expression and HIF-1α expression (r=0.553, p<0.0001), in the same tumor tissue areas of hepatocellular carcinoma patients. Our data suggested a new mechanism of hepatocellular carcinoma cells response to hypoxia.

  15. Peroxisome proliferator-activated receptor {alpha}-independent peroxisome proliferation

    SciTech Connect

    Zhang Xiuguo; Tanaka, Naoki . E-mail: naopi@hsp.md.shinshu-u.ac.jp; Nakajima, Takero; Kamijo, Yuji; Gonzalez, Frank J.; Aoyama, Toshifumi

    2006-08-11

    Hepatic peroxisome proliferation, increases in the numerical and volume density of peroxisomes, is believed to be closely related to peroxisome proliferator-activated receptor {alpha} (PPAR{alpha}) activation; however, it remains unknown whether peroxisome proliferation depends absolutely on this activation. To verify occurrence of PPAR{alpha}-independent peroxisome proliferation, fenofibrate treatment was used, which was expected to significantly enhance PPAR{alpha} dependence in the assay system. Surprisingly, a novel type of PPAR{alpha}-independent peroxisome proliferation and enlargement was uncovered in PPAR{alpha}-null mice. The increased expression of dynamin-like protein 1, but not peroxisome biogenesis factor 11{alpha}, might be associated with the PPAR{alpha}-independent peroxisome proliferation at least in part.

  16. Histone deacetylase inhibitor panobinostat induces calcineurin degradation in multiple myeloma

    PubMed Central

    Ohta, Eri; Takeda, Shu; Sunamura, Satoko; Ishibashi, Mariko; Tamura, Hideto; Wang, Yan-hua; Deguchi, Atsuko; Tanaka, Junji; Maru, Yoshiro; Motoji, Toshiko

    2016-01-01

    Multiple myeloma (MM) is a relapsed and refractory disease, one that highlights the need for developing new molecular therapies for overcoming of drug resistance. Addition of panobinostat, a histone deacetylase (HDAC) inhibitor, to bortezomib and dexamethasone improved progression-free survival (PFS) in relapsed and refractory MM patients. Here, we demonstrate how calcineurin, when inhibited by immunosuppressive drugs like FK506, is involved in myeloma cell growth and targeted by panobinostat. mRNA expression of PPP3CA, a catalytic subunit of calcineurin, was high in advanced patients. Panobinostat degraded PPP3CA, a degradation that should have been induced by inhibition of the chaperone function of heat shock protein 90 (HSP90). Cotreatment with HDAC inhibitors and FK506 led to an enhanced antimyeloma effect with a greater PPP3CA reduction compared with HDAC inhibitors alone both in vitro and in vivo. In addition, this combination treatment efficiently blocked osteoclast formation, which results in osteolytic lesions. The poor response and short PFS duration observed in the bortezomib-containing therapies of patients with high PPP3CA suggested its relevance to bortezomib resistance. Moreover, bortezomib and HDAC inhibitors synergistically suppressed MM cell viability through PPP3CA inhibition. Our findings underscore the usefulness of calcineurin-targeted therapy in MM patients, including patients who are resistant to bortezomib. PMID:27699258

  17. Histone deacetylase inhibitor panobinostat induces calcineurin degradation in multiple myeloma

    PubMed Central

    Ohta, Eri; Takeda, Shu; Sunamura, Satoko; Ishibashi, Mariko; Tamura, Hideto; Wang, Yan-hua; Deguchi, Atsuko; Tanaka, Junji; Maru, Yoshiro; Motoji, Toshiko

    2016-01-01

    Multiple myeloma (MM) is a relapsed and refractory disease, one that highlights the need for developing new molecular therapies for overcoming of drug resistance. Addition of panobinostat, a histone deacetylase (HDAC) inhibitor, to bortezomib and dexamethasone improved progression-free survival (PFS) in relapsed and refractory MM patients. Here, we demonstrate how calcineurin, when inhibited by immunosuppressive drugs like FK506, is involved in myeloma cell growth and targeted by panobinostat. mRNA expression of PPP3CA, a catalytic subunit of calcineurin, was high in advanced patients. Panobinostat degraded PPP3CA, a degradation that should have been induced by inhibition of the chaperone function of heat shock protein 90 (HSP90). Cotreatment with HDAC inhibitors and FK506 led to an enhanced antimyeloma effect with a greater PPP3CA reduction compared with HDAC inhibitors alone both in vitro and in vivo. In addition, this combination treatment efficiently blocked osteoclast formation, which results in osteolytic lesions. The poor response and short PFS duration observed in the bortezomib-containing therapies of patients with high PPP3CA suggested its relevance to bortezomib resistance. Moreover, bortezomib and HDAC inhibitors synergistically suppressed MM cell viability through PPP3CA inhibition. Our findings underscore the usefulness of calcineurin-targeted therapy in MM patients, including patients who are resistant to bortezomib.

  18. [Hereditary peroxisomal diseases].

    PubMed

    Astudillo, Leonardo; Sabourdy, Frédérique; Touati, Guy; Levade, Thierry

    2016-03-01

    Peroxisomes are small intracellular organelles that catalyse key metabolic reactions such as the beta-oxidation of some straight-chain or branched-chain fatty acids and the alpha-oxidation of phytanic acid. These enzyme reactions produce hydrogen peroxide, which is subsequently neutralized by the peroxisomal catalase. Peroxisomes also metabolize glyoxylate to glycine, and catalyze the first steps of plasmalogen biosynthesis. There are more than a dozen inherited peroxisomal disorders in humans. These metabolic diseases are due to monogenic defects that affect either a single function (such as enzyme or a transporter) or more than two distinct functions because of the impairment of several aspects of peroxisome biogenesis. With the notable exception of X-linked adrenoleucodystrophy, these inborn disorders are transmitted as autosomal recessive traits. Their clinical presentation can be very heterogeneous, and include neonatal, infantile or adult forms. The present review describes the symptomatology of these genetic diseases, the underlying genetic and biochemical alterations, and summarizes their diagnostic approach. PMID:26899150

  19. Enhanced pan-peroxisome proliferator-activated receptor gene and protein expression in adipose tissue of diet-induced obese mice treated with telmisartan.

    PubMed

    Penna-de-Carvalho, Aline; Graus-Nunes, Francielle; Rabelo-Andrade, Júlia; Mandarim-de-Lacerda, Carlos Alberto; Souza-Mello, Vanessa

    2014-12-01

    Telmisartan has previously been used to target obesity, showing peroxisome proliferator-activated receptor (PPAR) β/δ-related effects in white adipose tissue (WAT). We sought to evaluate whether telmisartan enhances gene and protein expression of all PPAR isoforms in WAT and brown adipose tissue (BAT), as well as their downstream effects upon insulin resistance, adipokine profile and adaptive thermogenesis. Male C57BL/6 mice were fed standard chow (SC; 10% lipids) or high-fat diet (HF; 50% lipids) for 10 weeks. Animals were then randomly allocated into the following four groups: SC, SC-T, HF and HF-T. Telmisartan [10 mg (kg diet)(-1)] was administered for 4 weeks in the diet. Animals in the HF group were overweight and exhibited hypertension, insulin resistance, decreased energy expenditure, a pro-inflammatory adipokine profile and abnormal fat pad mass distribution. Animals in the HF group showed decreased expression of PPARα, β/δ and γ in WAT and BAT, resulting in impaired glucose uptake and insufficient thermogenesis. Due to the improvement in the adipokine profile and enhanced insulin sensitivity with adequate insulin-stimulated glucose uptake after treatment with telmisartan, the activation of all PPAR isoforms in WAT was beneficial. In BAT, telmisartan induced sustained sympathetic activation, because the β3-adrenergic receptor was induced by PPARβ/δ, while uncoupling protein 1 was induced by PPARα to promote thermogenesis. Telmisartan exerted anti-obesity effects through higher pan-PPAR gene and protein expression. Upon PPARα, β/δ and γ (pan-PPAR) agonism in adipose tissue of obese mice, telmisartan ameliorates inflammation and insulin resistance, as well as inducing non-shivering thermogenesis. Our results point to new therapeutic targets for the control of obesity and comorbidities through pan-PPAR-related effects. PMID:25326526

  20. Transcriptome profiling to identify genes involved in peroxisome assembly and function.

    PubMed

    Smith, Jennifer J; Marelli, Marcello; Christmas, Rowan H; Vizeacoumar, Franco J; Dilworth, David J; Ideker, Trey; Galitski, Timothy; Dimitrov, Krassen; Rachubinski, Richard A; Aitchison, John D

    2002-07-22

    Yeast cells were induced to proliferate peroxisomes, and microarray transcriptional profiling was used to identify PEX genes encoding peroxins involved in peroxisome assembly and genes involved in peroxisome function. Clustering algorithms identified 224 genes with expression profiles similar to those of genes encoding peroxisomal proteins and genes involved in peroxisome biogenesis. Several previously uncharacterized genes were identified, two of which, YPL112c and YOR084w, encode proteins of the peroxisomal membrane and matrix, respectively. Ypl112p, renamed Pex25p, is a novel peroxin required for the regulation of peroxisome size and maintenance. These studies demonstrate the utility of comparative gene profiling as an alternative to functional assays to identify genes with roles in peroxisome biogenesis.

  1. Peroxisome protein import: a complex journey

    PubMed Central

    Baker, Alison; Hogg, Thomas Lanyon; Warriner, Stuart L.

    2016-01-01

    The import of proteins into peroxisomes possesses many unusual features such as the ability to import folded proteins, and a surprising diversity of targeting signals with differing affinities that can be recognized by the same receptor. As understanding of the structure and function of many components of the protein import machinery has grown, an increasingly complex network of factors affecting each step of the import pathway has emerged. Structural studies have revealed the presence of additional interactions between cargo proteins and the PEX5 receptor that affect import potential, with a subtle network of cargo-induced conformational changes in PEX5 being involved in the import process. Biochemical studies have also indicated an interdependence of receptor–cargo import with release of unloaded receptor from the peroxisome. Here, we provide an update on recent literature concerning mechanisms of protein import into peroxisomes. PMID:27284042

  2. Peroxisomal bifunctional enzyme deficiency.

    PubMed Central

    Watkins, P A; Chen, W W; Harris, C J; Hoefler, G; Hoefler, S; Blake, D C; Balfe, A; Kelley, R I; Moser, A B; Beard, M E

    1989-01-01

    Peroxisomal function was evaluated in a male infant with clinical features of neonatal adrenoleukodystrophy. Very long chain fatty acid levels were elevated in both plasma and fibroblasts, and beta-oxidation of very long chain fatty acids in cultured fibroblasts was significantly impaired. Although the level of the bile acid intermediate trihydroxycoprostanoic acid was slightly elevated in plasma, phytanic acid and L-pipecolic acid levels were normal, as was plasmalogen synthesis in cultured fibroblasts. The latter three parameters distinguish this case from classical neonatal adrenoleukodystrophy. In addition, electron microscopy and catalase subcellular distribution studies revealed that, in contrast to neonatal adrenoleukodystrophy, peroxisomes were present in the patient's tissues. Immunoblot studies of peroxisomal beta-oxidation enzymes revealed that the bifunctional enzyme (enoyl-CoA hydratase/3-hydroxyacyl-CoA dehydrogenase) was deficient in postmortem liver samples, whereas acyl-CoA oxidase and the mature form of beta-ketothiolase were present. Density gradient centrifugation of fibroblast homogenates confirmed that intact peroxisomes were present. Immunoblots of fibroblasts peroxisomal fractions showed that they contained acyl-CoA oxidase and beta-ketothiolase, but bifunctional enzyme was not detected. Northern analysis, however, revealed that mRNA coding for the bifunctional enzyme was present in the patient's fibroblasts. These results indicate that the primary biochemical defect in this patient is a deficiency of peroxisomal bifunctional enzyme. It is of interest that the phenotype of this patient resembled neonatal adrenoleukodystrophy and would not have been distinguished from this disorder by clinical study alone. Images PMID:2921319

  3. Induction of peroxisomes by butyrate-producing probiotics.

    PubMed

    Weng, Huachun; Endo, Kosuke; Li, Jiawei; Kito, Naoko; Iwai, Naoharu

    2015-01-01

    We previously found that peroxisomal biogenesis factor 11a (Pex11a) deficiency is associated with a reduction in peroxisome abundance and impaired fatty acid metabolism in hepatocytes, and results in steatosis. In the present study, we investigated whether butyrate induces Pex11a expression and peroxisome proliferation, and studied its effect on lipid metabolism. C57BL/6 mice fed standard chow or a high-fat diet (HFD) were treated with tributyrin, 4-phelybutyrate acid (4-PBA), or the butyrate-producing probiotics (Clostridium butyricum MIYAIRI 588 [CBM]) plus inulin (dietary fiber), and the body weight, white adipose tissue, serum triglycerides, mRNA expression, and peroxisome abundance were evaluated. Tributyrin or 4-PBA treatment significantly decreased body weight and increased hepatic mRNA expression of peroxisome proliferator-activated receptor-α (PPARα) and Pex11a. In addition, 4-PBA treatment increased peroxisome abundance and the expression of genes involved in peroxisomal fatty acid β-oxidation (acyl-coenzyme A oxidase 1 and hydroxysteroid [17-beta] dehydrogenase 4). CBM and inulin administration reduced adipose tissue mass and serum triglycerides, induced Pex11a, acyl-coenzyme A oxidase 1, and hydroxysteroid (17-beta) dehydrogenase 4 genes, and increased peroxisome abundance in mice fed standard chow or an HFD. In conclusion, elevation of butyrate availability (directly through administration of butyrate or indirectly via administration of butyrate-producing probiotics plus fiber) induces PPARα and Pex11a and the genes involved in peroxisomal fatty acid β-oxidation, increases peroxisome abundance, and improves lipid metabolism. These results may provide a new therapeutic strategy against hyperlipidemia and obesity.

  4. Candesartan cilexetil prevents diet-induced insulin resistance via peroxisome proliferator-activated receptor-γ activation in an obese rat model

    PubMed Central

    YAN, WEN-HUA; PAN, CHANG-YU; DOU, JING-TAO; MENG, JUN-HUA; WANG, BAO-AN; MU, YI-MING

    2016-01-01

    Angiotensin II type 1 receptor (AT1R) blockers (ARBs) have been shown to reduce the incidence of type 2 diabetes mellitus; however, the underlying molecular mechanism is unknown. Peroxisome proliferator-activated receptor γ (PPARγ) is the central regulator of insulin and glucose metabolism, which improves insulin sensitivity. Whether candesartan cilexetil, as a prodrug of the AT1R blocker candesartan, has PPARγ-activating properties remains to be elucidated. The aim of the present study was to investigate the effects of oral administration of candesartan cilexetil on glucose tolerance and the actions of PPARγ on liver and adipose tissue in the insulin-resistant obese rat induced by high-fat diet. Animals treated with candesartan cilexetil showed an improved glucose tolerance after oral glucose challenge. Whole-body insulin sensitivity was evaluated using the hyperinsulinemic-euglycemic clamp technique. During high-fat feeding in high-fat diet (HF) rats, the glucose infusion rate (GIR) was 52.3% lower than that in normal chow (NC) rats. However, the GIR was significantly enhanced following candesartan cilexetil treatment. Angiotensin II receptor antagonism also resulted in significant increases in PPARγ protein expression in adipose and liver tissue. These results indicate that PPARγ activation by candesartan cilexetil may provide novel therapeutic options in the treatment of patients with metabolic syndrome. PMID:27347049

  5. Over-expression of C/EBP-{alpha} induces apoptosis in cultured rat hepatic stellate cells depending on p53 and peroxisome proliferator-activated receptor-{gamma}

    SciTech Connect

    Wang Xueqing; Huang Guangcun; Mei Shuang; Qian Jin; Ji Juling; Zhang Jinsheng

    2009-03-06

    Hepatic stellate cells (HSCs) play a key role in the pathogenesis of hepatic fibrosis. In our previous studies, CCAAT enhancer binding protein-{alpha} (C/EBP-{alpha}) has been shown to be involved in the activation of HSCs and to have a repression effect on hepatic fibrosis in vivo. However, the mechanisms are largely unknown. In this study, we show that the infection of adenovirus vector expressing C/EBP-{alpha} gene (Ad-C/EBP-{alpha}) could induce HSCs apoptosis in a dose- and time-dependent manner by Annexin V/PI staining, caspase-3 activation assay, and flow cytometry. Also, over-expression of C/EBP-{alpha} resulted in the up-regulation of peroxisome proliferator-activated receptor-{gamma} (PPAR-{gamma}) and P53, while P53 expression was regulated by PPAR-{gamma}. In addition, Fas, FasL, DR4, DR5, and TRAIL were studied. The results indicated that the death receptor pathway was mainly involved and regulated by PPAR-{gamma} and p53 in the process of apoptosis triggered by C/EBP-{alpha} in HSCs.

  6. Terminal differentiation of human liposarcoma cells induced by ligands for peroxisome proliferator-activated receptor γ and the retinoid X receptor

    PubMed Central

    Tontonoz, Peter; Singer, Samuel; Forman, Barry M.; Sarraf, Pasha; Fletcher, Jonathan A.; Fletcher, Christopher D. M.; Brun, Regina P.; Mueller, Elisabetta; Altiok, Soner; Oppenheim, Heather; Evans, Ronald M.; Spiegelman, Bruce M.

    1997-01-01

    Induction of terminal differentiation represents a promising therapeutic approach to certain human malignancies. The peroxisome proliferator-activated receptor γ (PPARγ) and the retinoid X receptor α (RXRα) form a heterodimeric complex that functions as a central regulator of adipocyte differentiation. Natural and synthetic ligands for both receptors have been identified. We demonstrate here that PPARγ is expressed at high levels in each of the major histologic types of human liposarcoma. Moreover, primary human liposarcoma cells can be induced to undergo terminal differentiation by treatment with the PPARγ ligand pioglitazone, suggesting that the differentiation block in these cells can be overcome by maximal activation of the PPAR pathway. We further demonstrate that RXR-specific ligands are also potent adipogenic agents in cells expressing the PPARγ/RXRα heterodimer, and that simultaneous treatment of liposarcoma cells with both PPARγ- and RXR-specific ligands results in an additive stimulation of differentiation. Liposarcoma cell differentiation is characterized by accumulation of intracellular lipid, induction of adipocyte-specific genes, and withdrawal from the cell cycle. These results suggest that PPARγ ligands such as thiazolidinediones and RXR-specific retinoids may be useful therapeutic agents for the treatment of liposarcoma. PMID:8990192

  7. Antagonist of peroxisome proliferator-activated receptor {gamma} induces cerebellar amyloid-{beta} levels and motor dysfunction in APP/PS1 transgenic mice

    SciTech Connect

    Du, Jing; Sun, Bing; Chen, Kui; Fan, Li; Wang, Zhao

    2009-07-03

    Recent evidences show that peroxisome proliferator-activated receptor {gamma} (PPAR{gamma}) is involved in the modulation of the amyloid-{beta} (A{beta}) cascade causing Alzheimer's disease (AD) and treatment with PPAR{gamma} agonists protects against AD pathology. However, the function of PPAR{gamma} steady-state activity in A{beta} cascade and AD pathology remains unclear. In this study, an antagonist of PPAR{gamma}, GW9662, was injected into the fourth ventricle of APP/PS1 transgenic mice to inhibit PPAR{gamma} activity in cerebellum. The results show that inhibition of PPAR{gamma} significantly induced A{beta} levels in cerebellum and caused cerebellar motor dysfunction in APP/PS1 transgenic mice. Moreover, GW9662 treatment markedly decreased the cerebellar levels of insulin-degrading enzyme (IDE), which is responsible for the cellular degradation of A{beta}. Since cerebellum is spared from significant A{beta} accumulation and neurotoxicity in AD patients and animal models, these findings suggest a crucial role of PPAR{gamma} steady-state activity in protection of cerebellum against AD pathology.

  8. Catalase potentiates retinoic acid-induced THP-1 monocyte differentiation into macrophage through inhibition of peroxisome proliferator-activated receptor gamma.

    PubMed

    Ding, Qiurong; Jin, Ting; Wang, Zhenzhen; Chen, Yan

    2007-06-01

    Macrophage differentiation plays a pivotal role in cardiovascular diseases and many other physiological processes. However, the role of reaction oxygen species in macrophage differentiation has not been elucidated. Here, we report functional characterization of catalase, an enzyme that degrades hydrogen peroxide (H(2)O(2)), in THP-1 monocyte differentiation. Treatment of THP-1 cells with catalase was able to synergize with all-trans retinoic acid (ATRA) to enhance macrophage differentiation, demonstrated by changes of cell adherence, cell cycle arrest, nitroblue tetrazolium reduction, and expression of differentiation markers including CD68, CD11b, and matrix metalloproteinase 9 (MMP9). ATRA could stimulate retinoic acid (RA) receptor-mediated transcription, but this was not affected by catalase. However, ATRA and catalase were capable of reducing transcriptional activity mediated by peroxisome proliferator-activated receptor gamma (PPARgamma). Consistently, PPARgamma antagonists enhanced, and PPARgamma agonists inhibited MMP9 expression stimulated by ATRA and catalase in THP-1 cells. Therefore, these data indicate that catalase is able to potentiate ATRA-induced macrophage differentiation by inhibition of PPARgamma activity, underscoring an important interplay between H(2)O(2), RA, and PPARgamma in macrophages.

  9. Skeletal muscle Heat shock protein 60 increases after endurance training and induces peroxisome proliferator-activated receptor gamma coactivator 1 α1 expression

    PubMed Central

    Barone, Rosario; Macaluso, Filippo; Sangiorgi, Claudia; Campanella, Claudia; Marino Gammazza, Antonella; Moresi, Viviana; Coletti, Dario; Conway de Macario, Everly; Macario, Alberto JL; Cappello, Francesco; Adamo, Sergio; Farina, Felicia; Zummo, Giovanni; Di Felice, Valentina

    2016-01-01

    Heat shock protein 60 (Hsp60) is a chaperone localizing in skeletal muscle mitochondria, whose role is poorly understood. In the present study, the levels of Hsp60 in fibres of the entire posterior group of hindlimb muscles (gastrocnemius, soleus, and plantaris) were evaluated in mice after completing a 6-week endurance training program. The correlation between Hsp60 levels and the expression of four isoforms of peroxisome proliferator-activated receptor gamma coactivator 1 alpha (PGC1α) were investigated only in soleus. Short-term overexpression of hsp60, achieved by in vitro plasmid transfection, was then performed to determine whether this chaperone could have a role in the activation of the expression levels of PGC1α isoforms. The levels of Hsp60 protein were fibre-type specific in the posterior muscles and endurance training increased its content in type I muscle fibers. Concomitantly with the increased levels of Hsp60 released in the blood stream of trained mice, mitochondrial copy number and the expression of three isoforms of PGC1α increased. Overexpressing hsp60 in cultured myoblasts induced only the expression of PGC1 1α, suggesting a correlation between Hsp60 overexpression and PGC1 1 α activation. PMID:26812922

  10. Effects of Peroxisomal Catalase Inhibition on Mitochondrial Function

    PubMed Central

    Walton, Paul A.; Pizzitelli, Michael

    2012-01-01

    Peroxisomes produce hydrogen peroxide as a metabolic by-product of their many oxidase enzymes, but contain catalase that breaks down hydrogen peroxide in order to maintain the organelle’s oxidative balance. It has been previously demonstrated that, as cells age, catalase is increasingly absent from the peroxisome, and resides instead as an unimported tetrameric molecule in the cell cytosol; an alteration that is coincident with increased cellular hydrogen peroxide levels. As this process begins in middle-passage cells, we sought to determine whether peroxisomal hydrogen peroxide could contribute to the oxidative damage observed in mitochondria in late-passage cells. Early-passage human fibroblasts (Hs27) treated with aminotriazole (3-AT), an irreversible catalase inhibitor, demonstrated decreased catalase activity, increased levels of cellular hydrogen peroxide, protein carbonyls, and peroxisomal numbers. This treatment increased mitochondrial reactive oxygen species levels, and decreased the mitochondrial aconitase activity by ∼85% within 24 h. In addition, mitochondria from 3-AT treated cells show a decrease in inner membrane potential. These results demonstrate that peroxisome-derived oxidative imbalance may rapidly impair mitochondrial function, and considering that peroxisomal oxidative imbalance begins to occur in middle-passage cells, supports the hypothesis that peroxisomal oxidant release occurs upstream of, and contributes to, the mitochondrial damage observed in aging cells. PMID:22536190

  11. Gene expression profiling of potential peroxisome proliferator-activated receptor (PPAR) target genes in human hepatoblastoma cell lines inducibly expressing different PPAR isoforms

    PubMed Central

    Tachibana, Keisuke; Kobayashi, Yumi; Tanaka, Toshiya; Tagami, Masayuki; Sugiyama, Akira; Katayama, Tatsuya; Ueda, Chihiro; Yamasaki, Daisuke; Ishimoto, Kenji; Sumitomo, Mikako; Uchiyama, Yasutoshi; Kohro, Takahide; Sakai, Juro; Hamakubo, Takao; Kodama, Tatsuhiko; Doi, Takefumi

    2005-01-01

    Background Peroxisome proliferator-activated receptors (PPARs) are ligand-activated transcription factors and commonly play an important role in the regulation of lipid homeostasis. To identify human PPARs-responsive genes, we established tetracycline-regulated human hepatoblastoma cell lines that can be induced to express each human PPAR and investigated the gene expression profiles of these cells. Results The expression of each introduced PPAR gene was investigated using the various concentrations of doxycycline in the culture media. We found that the expression of each PPAR subtype was tightly controlled by the concentration of doxycycline in these established cell lines. DNA microarray analyses using these cell lines were performed with or without adding each subtype ligand and provided much important information on the PPAR target genes involved in lipid metabolism, transport, storage and other activities. Interestingly, it was noted that while ligand-activated PPARδ induced target gene expression, unliganded PPARδ repressed these genes. The real-time RT-PCR was used to verify the altered expression of selected genes by PPARs and we found that these genes were induced to express in the same pattern as detected in the microarray analyses. Furthermore, we analysed the 5'-flanking region of the human adipose differentiation-related protein (adrp) gene that responded to all subtypes of PPARs. From the detailed analyses by reporter assays, the EMSAs, and ChIP assays, we determined the functional PPRE of the human adrp gene. Conclusion The results suggest that these cell lines are important tools used to identify the human PPARs-responsive genes. PMID:16197558

  12. CTSK inhibitor exert its anti-obesity effects through regulating adipocyte differentiation in high-fat diet induced obese mice.

    PubMed

    Han, Junfeng; Wei, Li; Xu, Weibin; Lu, Junxi; Wang, Chen; Bao, Yuqian; Jia, Weiping

    2015-01-01

    Obesity is associated with increased risk of developing numerous adverse health conditions. Cathepsin k (CTSK) is highly expressed in adipose tissues of obese patients and animal models. Although CTSK has been demonstrated to promote adipocyte differentiation in 3T3-L1 cells, the effects of CTSK selective inhibitor (CKSI) on weight gain and insulin resistance have not been well examined. High-fat diet (HFD) induced obese male C57BL/6 mice were fed a diet with or without CKSI for 8 weeks. The HFD induced increase in adipose tissue weight gain, increase in homeostasis model assessment (HOMA) index as well as accumulation of large adipocytes. After CKSI treatment, all these effects were blunted compared with the HFD control group. A study of the mechanism demonstrated a role for CKSI in significantly down-regulating the expression of two key transcription factors, peroxisome proliferators-activated receptor-γ (PPARγ) and CCAAT/enhancer-binding protein α (C/EBPα), which are markers of adipogenic differentiation. These results indicated that the CKSI possesses an anti-obesity effect, possibly involving the inhibition of adipocyte differentiation. CTSK is likely to be a new target of therapeutic intervention for the treatment of obesity.

  13. Formation of Tankyrase Inhibitor-Induced Degradasomes Requires Proteasome Activity

    PubMed Central

    Pedersen, Nina Marie; Thorvaldsen, Tor Espen; Schultz, Sebastian Wolfgang; Wenzel, Eva Maria; Stenmark, Harald

    2016-01-01

    In canonical Wnt signaling, the protein levels of the key signaling mediator β-catenin are under tight regulation by the multimeric destruction complex that mediates proteasomal degradation of β-catenin. In colorectal cancer, destruction complex activity is often compromised due to mutations in the multifunctional scaffolding protein Adenomatous Polyposis Coli (APC), leading to a stabilization of β-catenin. Recently, tankyrase inhibitors (TNKSi), a novel class of small molecule inhibitors, were shown to re-establish a functional destruction complex in APC-mutant cancer cell lines by stabilizing AXIN1/2, whose protein levels are usually kept low via poly(ADP-ribosyl)ation by the tankyrase enzymes (TNKS1/2). Surprisingly, we found that for the formation of the morphological correlates of destruction complexes, called degradasomes, functional proteasomes are required. In addition we found that AXIN2 is strongly upregulated after 6 h of TNKS inhibition. The proteasome inhibitor MG132 counteracted TNKSi-induced degradasome formation and AXIN2 stabilization, and this was accompanied by reduced transcription of AXIN2. Mechanistically we could implicate the transcription factor FoxM1 in this process, which was recently shown to be a transcriptional activator of AXIN2. We observed a substantial reduction in TNKSi-induced stabilization of AXIN2 after siRNA-mediated depletion of FoxM1 and found that proteasome inhibition reduced the active (phosphorylated) fraction of FoxM1. This can explain the decreased protein levels of AXIN2 after MG132 treatment. Our findings have implications for the design of in vitro studies on the destruction complex and for clinical applications of TNKSi. PMID:27482906

  14. Peroxisome proliferator activated receptor-γ agonists protect oligodendrocyte progenitors against tumor necrosis factor-alpha-induced damage: Effects on mitochondrial functions and differentiation.

    PubMed

    De Nuccio, C; Bernardo, A; Cruciani, C; De Simone, R; Visentin, S; Minghetti, L

    2015-09-01

    The activation of the nuclear receptor peroxisome proliferator-activated receptor-γ (PPAR-γ) is known to exert anti-inflammatory and neuroprotective effects and PPAR-γ agonists are considered potential therapeutic agents in brain diseases including those affecting myelin. In demyelinating diseases such as multiple sclerosis (MS), inflammation is one of the causes of myelin and axonal damage. Oligodendrocyte (OL) differentiation is highly dependent on mitochondria, which are major targets of inflammatory insult. Here we show that PPAR-γ agonists protect OL progenitors against the maturational arrest induced by the inflammatory cytokine TNF-α by affecting mitochondrial functions. We demonstrate that the inhibition of OL differentiation by TNF-α is associated with i) increased mitochondrial superoxide production; ii) decreased mitochondrial membrane potential (mMP); and iii) decreased ADP-induced Ca(2+) oscillations, which we previously showed to be dependent on efficient mitochondria. The TNF-α effects were comparable to those of the mitochondrial toxin rotenone, further suggesting that TNF-α damage is mediated by mitochondrial function impairment. PPAR-γ agonists protected OL progenitors against the inhibitory activities of both TNF-α and rotenone on mMP, mitochondrial ROS production, Ca(2+) oscillations and OL differentiation. Finally, the PPAR-γ agonist pioglitazone increased the expression of PGC-1α (a mitochondrial biogenesis master regulator), UCP2 (a mitochondrial protein known to reduce ROS production), and cytochrome oxidase subunit COX1. These findings confirm the central role of mitochondria in OL differentiation and point to mitochondria as major targets of PPAR-γ agonist protection against TNF-α damage. PMID:26210873

  15. Rosiglitazone, a Peroxisome Proliferator-Activated Receptor (PPAR)-γ Agonist, Attenuates Inflammation Via NF-κB Inhibition in Lipopolysaccharide-Induced Peritonitis.

    PubMed

    Zhang, Yun-Fang; Zou, Xun-Liang; Wu, Jun; Yu, Xue-Qing; Yang, Xiao

    2015-12-01

    We assessed the anti-inflammatory effect of peroxisome proliferator-activated receptor (PPAR)-γ agonist, rosiglitazone, in a lipopolysaccharide (LPS)-induced peritonitis rat model. LPS was intraperitoneally injected into rats to establish peritonitis model. Male Sprague-Dawley (SD) rats were assigned to normal saline (the solvent of LPS), LPS, rosiglitazone plus LPS, and rosiglitazone alone. A simple peritoneal equilibrium test was performed with 20 ml 4.25 % peritoneal dialysis fluid. We measured the leukocyte count in dialysate and ultrafiltration volume. Peritoneal membrane histochemical staining was performed, and peritoneal thickness was assessed. CD40 and intercellular adhesion molecule-1 messenger RNA (ICAM-1 mRNA) levels in rat visceral peritoneum were detected by reverse transcription (RT)-PCR. IL-6 in rat peritoneal dialysis effluent was measured using enzyme-linked immunosorbent assay. The phosphorylation of NF-κB-p65 and IκBα was analyzed by Western blot. LPS administration resulted in increased peritoneal thickness and decreased ultrafiltration volume. Rosiglitazone pretreatment significantly decreased peritoneal thickness. In addition to CD40 and ICAM-1 mRNA expression, the IL-6, p-p65, and p-IκBα protein expressions were enhanced in LPS-administered animals. Rosiglitazone pretreatment significantly decreased ICAM-1 mRNA upregulation, secretion of IL-6 protein, and phosphorylation of NF-κB-p65 and IκBα without decreasing CD40 mRNA expression. Rosiglitazone has a protective effect in peritonitis, simultaneously decreasing NF-κB phosphorylation, suggesting that NF-κB signaling pathway mediated peritoneal inflammation induced by LPS. PPAR-γ might be considered a potential therapeutic target against peritonitis.

  16. Peroxisome proliferation in Arabidopsis: The challenging identification of ligand perception and downstream signaling is closer.

    PubMed

    León, José

    2008-09-01

    Peroxisomes are subcellular organelles with multiple functions mediated by their plasticity and dynamic behavior in plants. Changes in their shape, size, number and enzyme content occur in response to developmental and metabolic cues as well as environmental conditions. The number of peroxisomes per cell is thus mainly determined by its capacity to proliferate. In mammals, peroxisome proliferators such as the hypolipidemic drug clofibrate are perceived by the Peroxisome Proliferator-Activated Receptors (PPARs) nuclear receptors. Therein, activated transcription of the peroxisome biogenesis PEX11 genes and the recruitment of dynamin-related proteins lead to peroxisome proliferation. We recently reported that Arabidopsis thaliana, despite of lacking a PPAR homolog protein, activated the proliferation of peroxisomes in response to clofibrate. Concomitantly, clofibrate activated the expression of wound-responsive genes through the jasmonic acid signaling master regulator COI1 F-box protein. Besides, wounding activated the expression of the peroxisome biogenesis-related PEX1 and PEX14 genes, but not of PEX11 or DRP3A, which analogously to mammals, code for the main regulators of peroxisome proliferation in Arabidopsis. Thus, wounding did not activate peroxisome proliferation. Noteworthy, jasmonic acid-treated plants contained fewer but larger peroxisomes. Despite of the cross-talk between clofibrate- and wound-induced signaling, the proliferation of peroxisomes and the wound-activated defense remained uncoupled.

  17. Nucleoside reverse transcriptase inhibitors prevent HIV protease inhibitor-induced atherosclerosis by ubiquitination and degradation of protein kinase C.

    PubMed

    Bradshaw, Emily L; Li, Xiang-An; Guerin, Theresa; Everson, William V; Wilson, Melinda E; Bruce-Keller, Annadora J; Greenberg, Richard N; Guo, Ling; Ross, Stuart A; Smart, Eric J

    2006-12-01

    HIV protease inhibitors are important pharmacological agents used in the treatment of HIV-infected patients. One of the major disadvantages of HIV protease inhibitors is that they increase several cardiovascular risk factors, including the expression of CD36 in macrophages. The expression of CD36 in macrophages promotes the accumulation of cholesterol, the development of foam cells, and ultimately atherosclerosis. Recent studies have suggested that alpha-tocopherol can prevent HIV protease inhibitor-induced increases in macrophage CD36 levels. Because of the potential clinical utility of using alpha-tocopherol to limit some of the side effects of HIV protease inhibitors, we tested the ability of alpha-tocopherol to prevent ritonavir, a common HIV protease inhibitor, from inducing atherosclerosis in the LDL receptor (LDLR) null mouse model. Surprisingly, alpha-tocopherol did not prevent ritonavir-induced atherosclerosis. However, cotreatment with the nucleoside reverse transcriptase inhibitors (NRTIs), didanosine or D4T, did prevent ritonavir-induced atherosclerosis. Using macrophages isolated from LDLR null mice, we demonstrated that the NRTIs prevented the upregulation of CD36 and cholesterol accumulation in macrophages. Treatment of LDLR null mice with NRTIs promoted the ubiquitination and downregulation of protein kinase Calpha (PKC). Previous studies demonstrated that HIV protease inhibitor activation of PKC was necessary for the upregulation of CD36. Importantly, the in vivo inhibition of PKC with chelerythrine prevented ritonavir-induced upregulation of CD36, accumulation of cholesterol, and the formation of atherosclerotic lesions. These novel mechanistic studies suggest that NRTIs may provide protection from one of the negative side effects associated with HIV protease inhibitors, namely the increase in CD36 levels and subsequent cholesterol accumulation and atherogenesis.

  18. Multiple paths to peroxisomes: Mechanism of peroxisome maintenance in mammals.

    PubMed

    Hua, Rong; Kim, Peter K

    2016-05-01

    Peroxisomes are dynamic organelles that can adjust their size and number in response to cellular demand and environmental stimuli. They can propagate from pre-existing peroxisomes through growth and division, as well as de novo from the endoplasmic reticulum (ER). However, to what extend that these two distinct peroxisome biogenesis pathways are involved in maintaining peroxisome numbers in cycling cells is unclear. Recent studies in yeast suggest that the ER plays a direct role in the maintenance of peroxisomes. However, the role of the ER in mammalian system is under debate. In this review, we outline the recent progress in understanding the biogenesis of mammalian peroxisomes. We herein discuss some of the discrepancies in the literature and the outstanding questions in the field.

  19. Large-Scale Purification of Peroxisomes for Preparative Applications.

    PubMed

    Cramer, Jana; Effelsberg, Daniel; Girzalsky, Wolfgang; Erdmann, Ralf

    2015-09-01

    This protocol is designed for large-scale isolation of highly purified peroxisomes from Saccharomyces cerevisiae using two consecutive density gradient centrifugations. Instructions are provided for harvesting up to 60 g of oleic acid-induced yeast cells for the preparation of spheroplasts and generation of organellar pellets (OPs) enriched in peroxisomes and mitochondria. The OPs are loaded onto eight continuous 36%-68% (w/v) sucrose gradients. After centrifugation, the peak peroxisomal fractions are determined by measurement of catalase activity. These fractions are subsequently pooled and subjected to a second density gradient centrifugation using 20%-40% (w/v) Nycodenz. PMID:26330621

  20. Vascular and Central Activation of Peroxisome Proliferator-Activated Receptor-β Attenuates Angiotensin II-Induced Hypertension: Role of RGS-5.

    PubMed

    Romero, Miguel; Jiménez, Rosario; Toral, Marta; León-Gómez, Elvira; Gómez-Gúzman, Manuel; Sánchez, Manuel; Zarzuelo, María José; Rodríguez-Gómez, Isabel; Rath, Geraldine; Tamargo, Juan; Pérez-Vizcaíno, Francisco; Dessy, Chantal; Duarte, Juan

    2016-07-01

    Activation of peroxisome proliferator-activated receptor-β/δ (PPARβ) lowers blood pressure in genetic and mineralocorticoid-induced hypertension. Regulator of G-protein-coupled receptor signaling 5 (RGS5) protein, which interferes in angiotensin II (AngII) signaling, is a target gene to PPARβ The aim of the present study was to examine whether PPARβ activation in resistance arteries and brain tissues prevents the elevated blood pressure in AngII-induced hypertension and evaluate the role of RGS5 in this effect. C57BL/6J male mice were divided into five groups (control mice, PPARβ agonist [4-[[[2-[3-Fluoro-4-(trifluoromethyl)phenyl]-4-methyl-5-thiazolyl]methyl]thio]-2-methylphenoxy]acetic acid (GW0742)-treated mice AngII-infused mice, GW0742-treated AngII-infused mice, and AngII-infused mice treated with GW0742 plus PPARβ antagonist 3-[[[2-Methoxy-4-(phenylamino)phenyl]amino]sulfonyl]-2-thiophenecarboxylic acid methyl ester (GSK0660)) and were followed for 3 weeks. GW0742 prevented the increase in both arterial blood pressure and plasma noradrenaline levels and the higher reduction of blood pressure after ganglionic blockade, whereas it reduced the mesenteric arterial remodeling and the hyper-responsiveness to vasoconstrictors (AngII and endothelin-1) in AngII-infused mice. These effects were accompanied by an inhibition of NADPH oxidase expression and activity in the brain. Gene expression profiling revealed a marked loss of brainstem and vascular RGS5 in AngII-infused mice, which was restored by GW0742. GW0742-induced effects were abolished by GSK0660. Small interfering RNA targeting RGS5 caused augmented contractile response to AngII in resistance mesenteric arteries and blunted the inhibitory effect of GW0742 on this response. In conclusion, GW0742 exerted antihypertensive effects, restoring sympathetic tone and vascular structure and function in AngII-infused mice by PPARβ activation in brain and vessels inhibiting AngII signaling as a result of RGS5

  1. Selective Serotonin–norepinephrine Reuptake Inhibitors-induced Takotsubo Cardiomyopathy

    PubMed Central

    Vasudev, Rahul; Rampal, Upamanyu; Patel, Hiten; Patel, Kunal; Bikkina, Mahesh; Shamoon, Fayez

    2016-01-01

    Context: Takotsubo translates to “octopus pot” in Japanese. Takotsubo cardiomyopathy (TTC) is characterized by a transient regional systolic dysfunction of the left ventricle. Catecholamine excess is the one most studied and favored theories explaining the pathophysiology of TTC. Case Report: We present the case of a 52-year-old Hispanic female admitted for venlafaxine-induced TTC with a review literature on all the cases of Serotonin–norepinephrine reuptake inhibitors (SNRI)-associated TTC published so far. Conclusion: SNRI inhibit the reuptake of catecholamines into the presynaptic neuron, resulting in a net gain in the concentration of epinephrine and serotonin in the neuronal synapses and causing iatrogenic catecholamine excess, ultimately leading to TTC. PMID:27583240

  2. Role of the PAS1 gene of Pichia pastoris in peroxisome biogenesis

    PubMed Central

    1994-01-01

    Several groups have reported the cloning and sequencing of genes involved in the biogenesis of yeast peroxisomes. Yeast strains bearing mutations in these genes are unable to grow on carbon sources whose metabolism requires peroxisomes, and these strains lack morphologically normal peroxisomes. We report the cloning of Pichia pastoris PAS1, the homologue (based on a high level of protein sequence similarity) of the Saccharomyces cerevisiae PAS1. We also describe the creation and characterization of P. pastoris pas1 strains. Electron microscopy on the P. pastoris pas1 cells revealed that they lack morphologically normal peroxisomes, and instead contain membrane-bound structures that appear to be small, mutant peroxisomes, or "peroxisome ghosts." These "ghosts" proliferated in response to induction on peroxisome-requiring carbon sources (oleic acid and methanol), and they were distributed to daughter cells. Biochemical analysis of cell lysates revealed that peroxisomal proteins are induced normally in pas1 cells. Peroxisome ghosts from pas1 cells were purified on sucrose gradients, and biochemical analysis showed that these ghosts, while lacking several peroxisomal proteins, did import varying amounts of several other peroxisomal proteins. The existence of detectable peroxisome ghosts in P. pastoris pas1 cells, and their ability to import some proteins, stands in contrast with the results reported by Erdmann et al. (1991) for the S. cerevisiae pas1 mutant, in which they were unable to detect peroxisome-like structures. We discuss the role of PAS1 in peroxisome biogenesis in light of the new information regarding peroxisome ghosts in pas1 cells. PMID:7962088

  3. How Peroxisomes Affect Aflatoxin Biosynthesis in Aspergillus Flavus

    PubMed Central

    Reverberi, Massimo; Punelli, Marta; Smith, Carrie A.; Zjalic, Slaven; Scarpari, Marzia; Scala, Valeria; Cardinali, Giorgia; Aspite, Nicaela; Pinzari, Flavia; Payne, Gary A.; Fabbri, Anna A.; Fanelli, Corrado

    2012-01-01

    In filamentous fungi, peroxisomes are crucial for the primary metabolism and play a pivotal role in the formation of some secondary metabolites. Further, peroxisomes are important site for fatty acids β-oxidation, the formation of reactive oxygen species and for their scavenging through a complex of antioxidant activities. Oxidative stress is involved in different metabolic events in all organisms and it occurs during oxidative processes within the cell, including peroxisomal β-oxidation of fatty acids. In Aspergillus flavus, an unbalance towards an hyper-oxidant status into the cell is a prerequisite for the onset of aflatoxin biosynthesis. In our preliminary results, the use of bezafibrate, inducer of both peroxisomal β-oxidation and peroxisome proliferation in mammals, significantly enhanced the expression of pex11 and foxA and stimulated aflatoxin synthesis in A. flavus. This suggests the existence of a correlation among peroxisome proliferation, fatty acids β-oxidation and aflatoxin biosynthesis. To investigate this correlation, A. flavus was transformed with a vector containing P33, a gene from Cymbidium ringspot virus able to induce peroxisome proliferation, under the control of the promoter of the Cu,Zn-sod gene of A. flavus. This transcriptional control closely relates the onset of the antioxidant response to ROS increase, with the proliferation of peroxisomes in A. flavus. The AfP33 transformant strain show an up-regulation of lipid metabolism and an higher content of both intracellular ROS and some oxylipins. The combined presence of a higher amount of substrates (fatty acids-derived), an hyper-oxidant cell environment and of hormone-like signals (oxylipins) enhances the synthesis of aflatoxins in the AfP33 strain. The results obtained demonstrated a close link between peroxisome metabolism and aflatoxin synthesis. PMID:23094106

  4. Modulation of Receptor Phosphorylation Contributes to Activation of Peroxisome Proliferator Activated Receptor α by Dehydroepiandrosterone and Other Peroxisome Proliferators

    PubMed Central

    Tamasi, Viola; Miller, Kristy K. Michael; Ripp, Sharon L.; Vila, Ermin; Geoghagen, Thomas E.; Prough, Russell A.

    2008-01-01

    Dehydroepiandrosterone (DHEA), a C19 human adrenal steroid, activates peroxisome proliferator-activated receptor α (PPARα) in vivo but does not ligand-activate PPARα in transient transfection experiments. We demonstrate that DHEA regulates PPARα action by altering both the levels and phosphorylation status of the receptor. Human hepatoma cells (HepG2) were transiently transfected with the expression plasmid encoding PPARα and a plasmid containing two copies of fatty acyl coenzyme oxidase (FACO) peroxisome-proliferator activated receptor responsive element consensus oligonucleotide in a luciferase reporter gene. Nafenopin treatment increased reporter gene activity in this system, whereas DHEA treatment did not. Okadaic acid significantly decreased nafenopin-induced reporter activity in a concentration-dependent manner. Okadaic acid treatment of primary rat hepatocytes decreased both DHEA- and nafenopin-induced FACO activity in primary rat hepatocytes. DHEA induced both PPARα mRNA and protein levels, as well as PP2A message in primary rat hepatocytes. Western blot analysis showed that the serines at positions 12 and 21 were rapidly dephosphorylated upon treatment with DHEA and nafenopin. Results using specific protein phosphatase inhibitors suggested that protein phosphatase 2A (PP2A) is responsible for DHEA action, and protein phosphatase 1 might be involved in nafenopin induction. Mutation of serines at position 6, 12, and 21 to an uncharged alanine residue significantly increased transcriptional activity, whereas mutation to negative charged aspartate residues (mimicking receptor phosphorylation) decreased transcriptional activity. DHEA action involves induction of PPARα mRNA and protein levels as well as increased PPARα transcriptional activity through decreasing receptor phosphorylation at serines in the AF1 region. PMID:18079279

  5. Peroxisomes and Disease - An Overview

    PubMed Central

    Delille, Hannah K.; Bonekamp, Nina A.; Schrader, Michael

    2006-01-01

    Peroxisomes are indispensable for human health and development. They represent ubiquitous subcellular organelles which compartmentalize enzymes responsible for several crucial metabolic processes such as β-oxidation of specific fatty acids, biosynthesis of ether phospholipids and metabolism of reactive oxygen species. Peroxisomes are highly flexible organelles that rapidly assemble, multiply and degrade in response to metabolic needs. Basic research on the biogenesis of peroxisomes and their metabolic functions have improved our knowledge about their crucial role in several inherited disorders and in other pathophysiological conditions. The goal of this review is to give a comprehensive overview of the role of peroxisomes in disease. Besides the genetic peroxisomal disorders in humans, the role of peroxisomes in carcinogenesis and in situations related to oxidative stress such as inflammation, ischemia-reperfusion, and diabetes will be addressed. PMID:23674998

  6. Hypervulnerability to Sound Exposure through Impaired Adaptive Proliferation of Peroxisomes.

    PubMed

    Delmaghani, Sedigheh; Defourny, Jean; Aghaie, Asadollah; Beurg, Maryline; Dulon, Didier; Thelen, Nicolas; Perfettini, Isabelle; Zelles, Tibor; Aller, Mate; Meyer, Anaïs; Emptoz, Alice; Giraudet, Fabrice; Leibovici, Michel; Dartevelle, Sylvie; Soubigou, Guillaume; Thiry, Marc; Vizi, E Sylvester; Safieddine, Saaid; Hardelin, Jean-Pierre; Avan, Paul; Petit, Christine

    2015-11-01

    A deficiency in pejvakin, a protein of unknown function, causes a strikingly heterogeneous form of human deafness. Pejvakin-deficient (Pjvk(-/-)) mice also exhibit variable auditory phenotypes. Correlation between their hearing thresholds and the number of pups per cage suggest a possible harmful effect of pup vocalizations. Direct sound or electrical stimulation show that the cochlear sensory hair cells and auditory pathway neurons of Pjvk(-/-) mice and patients are exceptionally vulnerable to sound. Subcellular analysis revealed that pejvakin is associated with peroxisomes and required for their oxidative-stress-induced proliferation. Pjvk(-/-) cochleas display features of marked oxidative stress and impaired antioxidant defenses, and peroxisomes in Pjvk(-/-) hair cells show structural abnormalities after the onset of hearing. Noise exposure rapidly upregulates Pjvk cochlear transcription in wild-type mice and triggers peroxisome proliferation in hair cells and primary auditory neurons. Our results reveal that the antioxidant activity of peroxisomes protects the auditory system against noise-induced damage.

  7. Peroxisomal cholesterol biosynthesis and Smith-Lemli-Opitz syndrome

    SciTech Connect

    Weinhofer, Isabelle; Kunze, Markus; Stangl, Herbert; Porter, Forbes D.; Berger, Johannes . E-mail: johannes.berger@meduniwien.ac.at

    2006-06-23

    Smith-Lemli-Opitz syndrome (SLOS), caused by 7-dehydrocholesterol-reductase (DHCR7) deficiency, shows variable severity independent of DHCR7 genotype. To test whether peroxisomes are involved in alternative cholesterol synthesis, we used [1-{sup 14}C]C24:0 for peroxisomal {beta}-oxidation to generate [1-{sup 14}C]acetyl-CoA as cholesterol precursor inside peroxisomes. The HMG-CoA reductase inhibitor lovastatin suppressed cholesterol synthesis from [2-{sup 14}C]acetate and [1-{sup 14}C]C8:0 but not from [1-{sup 14}C]C24:0, implicating a peroxisomal, lovastatin-resistant HMG-CoA reductase. In SLOS fibroblasts lacking DHCR7 activity, no cholesterol was formed from [1-{sup 14}C]C24:0-derived [1-{sup 14}C]acetyl-CoA, indicating that the alternative peroxisomal pathway also requires this enzyme. Our results implicate peroxisomes in cholesterol biosynthesis but provide no link to phenotypic variation in SLOS.

  8. Phosphatidylcholine Supply to Peroxisomes of the Yeast Saccharomyces cerevisiae

    PubMed Central

    Ramprecht, Claudia; Zellnig, Günther; Leitner, Erich; Hermetter, Albin; Daum, Günther

    2015-01-01

    In the yeast Saccharomyces cerevisiae, phosphatidylcholine (PC), the major phospholipid (PL) of all organelle membranes, is synthesized via two different pathways. Methylation of phosphatidylethanolamine (PE) catalyzed by the methyl transferases Cho2p/Pem1p and Opi3p/Pem2p as well as incorporation of choline through the CDP (cytidine diphosphate)-choline branch of the Kennedy pathway lead to PC formation. To determine the contribution of these two pathways to the supply of PC to peroxisomes (PX), yeast mutants bearing defects in the two pathways were cultivated under peroxisome inducing conditions, i.e. in the presence of oleic acid, and subjected to biochemical and cell biological analyses. Phenotype studies revealed compromised growth of both the cho20Δopi3Δ (mutations in the methylation pathway) and the cki1Δdpl1Δeki1Δ (mutations in the CDP-choline pathway) mutant when grown on oleic acid. Analysis of peroxisomes from the two mutant strains showed that both pathways produce PC for the supply to peroxisomes, although the CDP-choline pathway seemed to contribute with higher efficiency than the methylation pathway. Changes in the peroxisomal lipid pattern of mutants caused by defects in the PC biosynthetic pathways resulted in changes of membrane properties as shown by anisotropy measurements with fluorescent probes. In summary, our data define the origin of peroxisomal PC and demonstrate the importance of PC for peroxisome membrane formation and integrity. PMID:26241051

  9. Phosphatidylcholine Supply to Peroxisomes of the Yeast Saccharomyces cerevisiae.

    PubMed

    Flis, Vid V; Fankl, Ariane; Ramprecht, Claudia; Zellnig, Günther; Leitner, Erich; Hermetter, Albin; Daum, Günther

    2015-01-01

    In the yeast Saccharomyces cerevisiae, phosphatidylcholine (PC), the major phospholipid (PL) of all organelle membranes, is synthesized via two different pathways. Methylation of phosphatidylethanolamine (PE) catalyzed by the methyl transferases Cho2p/Pem1p and Opi3p/Pem2p as well as incorporation of choline through the CDP (cytidine diphosphate)-choline branch of the Kennedy pathway lead to PC formation. To determine the contribution of these two pathways to the supply of PC to peroxisomes (PX), yeast mutants bearing defects in the two pathways were cultivated under peroxisome inducing conditions, i.e. in the presence of oleic acid, and subjected to biochemical and cell biological analyses. Phenotype studies revealed compromised growth of both the cho20Δopi3Δ (mutations in the methylation pathway) and the cki1Δdpl1Δeki1Δ (mutations in the CDP-choline pathway) mutant when grown on oleic acid. Analysis of peroxisomes from the two mutant strains showed that both pathways produce PC for the supply to peroxisomes, although the CDP-choline pathway seemed to contribute with higher efficiency than the methylation pathway. Changes in the peroxisomal lipid pattern of mutants caused by defects in the PC biosynthetic pathways resulted in changes of membrane properties as shown by anisotropy measurements with fluorescent probes. In summary, our data define the origin of peroxisomal PC and demonstrate the importance of PC for peroxisome membrane formation and integrity.

  10. Dual targeting of peroxisomal proteins

    PubMed Central

    Ast, Julia; Stiebler, Alina C.; Freitag, Johannes; Bölker, Michael

    2013-01-01

    Cellular compartmentalization into organelles serves to separate biological processes within the environment of a single cell. While some metabolic reactions are specific to a single organelle, others occur in more than one cellular compartment. Specific targeting of proteins to compartments inside of eukaryotic cells is mediated by defined sequence motifs. To achieve multiple targeting to different compartments cells use a variety of strategies. Here, we focus on mechanisms leading to dual targeting of peroxisomal proteins. In many instances, isoforms of peroxisomal proteins with distinct intracellular localization are encoded by separate genes. But also single genes can give rise to differentially localized proteins. Different isoforms can be generated by use of alternative transcriptional start sites, by differential splicing or ribosomal read-through of stop codons. In all these cases different peptide variants are produced, of which only one carries a peroxisomal targeting signal. Alternatively, peroxisomal proteins contain additional signals that compete for intracellular targeting. Dual localization of proteins residing in both the cytoplasm and in peroxisomes may also result from use of inefficient targeting signals. The recent observation that some bona fide cytoplasmic enzymes were also found in peroxisomes indicates that dual targeting of proteins to both the cytoplasm and the peroxisome might be more widespread. Although current knowledge of proteins exhibiting only partial peroxisomal targeting is far from being complete, we speculate that the metabolic capacity of peroxisomes might be larger than previously assumed. PMID:24151469

  11. Dual targeting of peroxisomal proteins.

    PubMed

    Ast, Julia; Stiebler, Alina C; Freitag, Johannes; Bölker, Michael

    2013-10-18

    Cellular compartmentalization into organelles serves to separate biological processes within the environment of a single cell. While some metabolic reactions are specific to a single organelle, others occur in more than one cellular compartment. Specific targeting of proteins to compartments inside of eukaryotic cells is mediated by defined sequence motifs. To achieve multiple targeting to different compartments cells use a variety of strategies. Here, we focus on mechanisms leading to dual targeting of peroxisomal proteins. In many instances, isoforms of peroxisomal proteins with distinct intracellular localization are encoded by separate genes. But also single genes can give rise to differentially localized proteins. Different isoforms can be generated by use of alternative transcriptional start sites, by differential splicing or ribosomal read-through of stop codons. In all these cases different peptide variants are produced, of which only one carries a peroxisomal targeting signal. Alternatively, peroxisomal proteins contain additional signals that compete for intracellular targeting. Dual localization of proteins residing in both the cytoplasm and in peroxisomes may also result from use of inefficient targeting signals. The recent observation that some bona fide cytoplasmic enzymes were also found in peroxisomes indicates that dual targeting of proteins to both the cytoplasm and the peroxisome might be more widespread. Although current knowledge of proteins exhibiting only partial peroxisomal targeting is far from being complete, we speculate that the metabolic capacity of peroxisomes might be larger than previously assumed.

  12. The birth of yeast peroxisomes.

    PubMed

    Yuan, Wei; Veenhuis, Marten; van der Klei, Ida J

    2016-05-01

    This contribution describes the phenotypic differences of yeast peroxisome-deficient mutants (pex mutants). In some cases different phenotypes were reported for yeast mutants deleted in the same PEX gene. These differences are most likely related to the marker proteins and methods used to detect peroxisomal remnants. This is especially evident for pex3 and pex19 mutants, where the localization of receptor docking proteins (Pex13, Pex14) resulted in the identification of peroxisomal membrane remnants, which do not contain other peroxisomal membrane proteins, such as the ring proteins Pex2, Pex10 and Pex12. These structures in pex3 and pex19 cells are the template for peroxisome formation upon introduction of the missing gene. Taken together, these data suggest that in all yeast pex mutants analyzed so far peroxisomes are not formed de novo but use membrane remnant structures as a template for peroxisome formation upon reintroduction of the missing gene. The relevance of this model for peroxisomal membrane protein and lipid sorting to peroxisomes is discussed.

  13. Fungal peroxisomes as biosynthetic organelles.

    PubMed

    Stehlik, Thorsten; Sandrock, Björn; Ast, Julia; Freitag, Johannes

    2014-12-01

    Peroxisomes are nearly ubiquitous single-membrane organelles harboring multiple metabolic pathways beside their prominent role in the β-oxidation of fatty acids. Here we review the diverse metabolic functions of peroxisomes in fungi. A variety of fungal metabolites are at least partially synthesized inside peroxisomes. These include the essential co-factor biotin but also different types of secondary metabolites. Peroxisomal metabolites are often derived from acyl-CoA esters for example β-oxidation intermediates. In several ascomycetes a subtype of peroxisomes has been identified that is metabolically inactive but is required to plug the septal pores of wounded hyphae. Thus, peroxisomes are versatile organelles that can adapt their function to the life style of an organism. This remarkable variability suggests that the full extent of the biosynthetic capacity of peroxisomes is still elusive. Moreover, in fungi peroxisomes are non-essential under laboratory conditions making them attractive organelles for biotechnological approaches and the design of novel metabolic pathways in customized peroxisomes.

  14. Peroxisomal metabolism and oxidative stress.

    PubMed

    Nordgren, Marcus; Fransen, Marc

    2014-03-01

    Peroxisomes are ubiquitous and multifunctional organelles that are primarily known for their role in cellular lipid metabolism. As many peroxisomal enzymes catalyze redox reactions as part of their normal function, these organelles are also increasingly recognized as potential regulators of oxidative stress-related signaling pathways. This in turn suggests that peroxisome dysfunction is not only associated with rare inborn errors of peroxisomal metabolism, but also with more common age-related diseases such as neurodegeneration, type 2 diabetes, and cancer. This review intends to provide a comprehensive picture of the complex role of mammalian peroxisomes in cellular redox metabolism. We highlight how peroxisomal metabolism may contribute to the bioavailability of important mediators of oxidative stress, with particular emphasis on reactive oxygen species. In addition, we review the biological properties of peroxisome-derived signaling messengers and discuss how these molecules may mediate various biological responses. Furthermore, we explore the emerging concepts that peroxisomes and mitochondria share an intricate redox-sensitive relationship and cooperate in cell fate decisions. This is particularly relevant to the observed demise of peroxisome function which accompanies cellular senescence, organismal aging, and age-related diseases. PMID:23933092

  15. The birth of yeast peroxisomes.

    PubMed

    Yuan, Wei; Veenhuis, Marten; van der Klei, Ida J

    2016-05-01

    This contribution describes the phenotypic differences of yeast peroxisome-deficient mutants (pex mutants). In some cases different phenotypes were reported for yeast mutants deleted in the same PEX gene. These differences are most likely related to the marker proteins and methods used to detect peroxisomal remnants. This is especially evident for pex3 and pex19 mutants, where the localization of receptor docking proteins (Pex13, Pex14) resulted in the identification of peroxisomal membrane remnants, which do not contain other peroxisomal membrane proteins, such as the ring proteins Pex2, Pex10 and Pex12. These structures in pex3 and pex19 cells are the template for peroxisome formation upon introduction of the missing gene. Taken together, these data suggest that in all yeast pex mutants analyzed so far peroxisomes are not formed de novo but use membrane remnant structures as a template for peroxisome formation upon reintroduction of the missing gene. The relevance of this model for peroxisomal membrane protein and lipid sorting to peroxisomes is discussed. PMID:26367802

  16. Peroxisomal metabolism and oxidative stress.

    PubMed

    Nordgren, Marcus; Fransen, Marc

    2014-03-01

    Peroxisomes are ubiquitous and multifunctional organelles that are primarily known for their role in cellular lipid metabolism. As many peroxisomal enzymes catalyze redox reactions as part of their normal function, these organelles are also increasingly recognized as potential regulators of oxidative stress-related signaling pathways. This in turn suggests that peroxisome dysfunction is not only associated with rare inborn errors of peroxisomal metabolism, but also with more common age-related diseases such as neurodegeneration, type 2 diabetes, and cancer. This review intends to provide a comprehensive picture of the complex role of mammalian peroxisomes in cellular redox metabolism. We highlight how peroxisomal metabolism may contribute to the bioavailability of important mediators of oxidative stress, with particular emphasis on reactive oxygen species. In addition, we review the biological properties of peroxisome-derived signaling messengers and discuss how these molecules may mediate various biological responses. Furthermore, we explore the emerging concepts that peroxisomes and mitochondria share an intricate redox-sensitive relationship and cooperate in cell fate decisions. This is particularly relevant to the observed demise of peroxisome function which accompanies cellular senescence, organismal aging, and age-related diseases.

  17. Peroxisome proliferator-activated receptor-α-mediated transcription of miR-199a2 attenuates endothelin-1 expression via hypoxia-inducible factor-1α.

    PubMed

    Li, Chen; Mpollo, Marthe-Sandrine Eiymo Mwa; Gonsalves, Caryn S; Tahara, Stanley M; Malik, Punam; Kalra, Vijay K

    2014-12-26

    Endothelin-1, a potent vasoconstrictor, plays an important role in pulmonary hypertension (PH) in sickle cell disease (SCD). Our previous studies show that higher levels of placenta growth factor (PlGF), secreted by erythroid precursor cells, correlate with increased plasma levels of endothelin-1 (ET-1) and other functional markers of PH in SCD. PlGF-mediated ET-1 expression occurs via activation of hypoxia-inducible factor-1α (HIF-1α). However, relatively less is understood regarding how PlGF-mediated expression of HIF-1α and its downstream effector ET-1 are post-transcriptionally regulated. Herein, we show that PlGF treatment of endothelial cells resulted in reduced levels of miR-199a2, which targeted the 3'-UTR of HIF-1α mRNA and concomitantly led to augmented ET-1 expression. Plasma levels of miR-199a2 in SCD subjects were significantly lower with reciprocally high levels of plasma ET-1, unlike unaffected controls. This observation provided a molecular link between miR-199a2 and high levels of ET-1 in SCD. Furthermore, we show that miR-199a2 located in the DNM3os transcription unit was co-transcriptionally regulated by peroxisome proliferator-activated receptor α (PPARα). Binding of the latter to PPARα cis-elements in the promoter of DNM3os was demonstrated by promoter mutational analysis and ChIP. Additionally, we show that fenofibrate, a PPARα agonist, increased the expression of miR-199a2 and DNM3os; the former was responsible for reduced expression of HIF-1α and ET-1. In vivo studies of fenofibrate-fed Berkeley sickle mice resulted in increased levels of miR-199a2 and reduced levels of ET-1 in lung tissues. Our studies provide a potential therapeutic approach whereby fenofibrate-induced miR-199a2 expression can ameliorate PH by reduction of ET-1 levels.

  18. Inhibitors of Fatty Acid Synthesis Induce PPAR α -Regulated Fatty Acid β -Oxidative Genes: Synergistic Roles of L-FABP and Glucose.

    PubMed

    Huang, Huan; McIntosh, Avery L; Martin, Gregory G; Petrescu, Anca D; Landrock, Kerstin K; Landrock, Danilo; Kier, Ann B; Schroeder, Friedhelm

    2013-01-01

    While TOFA (acetyl CoA carboxylase inhibitor) and C75 (fatty acid synthase inhibitor) prevent lipid accumulation by inhibiting fatty acid synthesis, the mechanism of action is not simply accounted for by inhibition of the enzymes alone. Liver fatty acid binding protein (L-FABP), a mediator of long chain fatty acid signaling to peroxisome proliferator-activated receptor- α (PPAR α ) in the nucleus, was found to bind TOFA and its activated CoA thioester, TOFyl-CoA, with high affinity while binding C75 and C75-CoA with lower affinity. Binding of TOFA and C75-CoA significantly altered L-FABP secondary structure. High (20 mM) but not physiological (6 mM) glucose conferred on both TOFA and C75 the ability to induce PPAR α transcription of the fatty acid β -oxidative enzymes CPT1A, CPT2, and ACOX1 in cultured primary hepatocytes from wild-type (WT) mice. However, L-FABP gene ablation abolished the effects of TOFA and C75 in the context of high glucose. These effects were not associated with an increased cellular level of unesterified fatty acids but rather by increased intracellular glucose. These findings suggested that L-FABP may function as an intracellular fatty acid synthesis inhibitor binding protein facilitating TOFA and C75-mediated induction of PPAR α in the context of high glucose at levels similar to those in uncontrolled diabetes.

  19. No peroxisome is an island — Peroxisome contact sites☆

    PubMed Central

    Shai, Nadav; Schuldiner, Maya; Zalckvar, Einat

    2016-01-01

    In order to optimize their multiple cellular functions, peroxisomes must collaborate and communicate with the surrounding organelles. A common way of communication between organelles is through physical membrane contact sites where membranes of two organelles are tethered, facilitating exchange of small molecules and intracellular signaling. In addition contact sites are important for controlling processes such as metabolism, organelle trafficking, inheritance and division. How peroxisomes rely on contact sites for their various cellular activities is only recently starting to be appreciated and explored and the extent of peroxisomal communication, their contact sites and their functions are less characterized. In this review we summarize the identified peroxisomal contact sites, their tethering complexes and their potential physiological roles. Additionally, we highlight some of the preliminary evidence that exists in the field for unexplored peroxisomal contact sites. PMID:26384874

  20. No peroxisome is an island - Peroxisome contact sites.

    PubMed

    Shai, Nadav; Schuldiner, Maya; Zalckvar, Einat

    2016-05-01

    In order to optimize their multiple cellular functions, peroxisomes must collaborate and communicate with the surrounding organelles. A common way of communication between organelles is through physical membrane contact sites where membranes of two organelles are tethered, facilitating exchange of small molecules and intracellular signaling. In addition contact sites are important for controlling processes such as metabolism, organelle trafficking, inheritance and division. How peroxisomes rely on contact sites for their various cellular activities is only recently starting to be appreciated and explored and the extent of peroxisomal communication, their contact sites and their functions are less characterized. In this review we summarize the identified peroxisomal contact sites, their tethering complexes and their potential physiological roles. Additionally, we highlight some of the preliminary evidence that exists in the field for unexplored peroxisomal contact sites.

  1. ABCD2 Alters Peroxisome Proliferator-Activated Receptor α Signaling In Vitro, but Does Not Impair Responses to Fenofibrate Therapy in a Mouse Model of Diet-Induced Obesity

    PubMed Central

    Liu, Xiaoxi; Liu, Jingjing; Liang, Shuang; Schlüter, Agatha; Fourcade, Stephane; Aslibekyan, Stella; Pujol, Aurora

    2014-01-01

    Fenofibrate is a peroxisome proliferator-activated receptor (PPAR) α ligand that has been widely used as a lipid-lowering agent in the treatment of hypertriglyceridemia. ABCD2 (D2) is a peroxisomal long-chain acyl-CoA transporter that is highly induced by fenofibrate in the livers of mice. To determine whether D2 is a modifier of fibrate responses, wild-type and D2-deficient mice were treated with fenofibrate for 14 days. The absence of D2 altered expression of gene clusters associated with lipid metabolism, including PPARα signaling. Using 3T3-L1 adipocytes, which express high levels of D2, we confirmed that knockdown of D2 modified genomic responses to fibrate treatment. We next evaluated the impact of D2 on effects of fibrates in a mouse model of diet-induced obesity. Fenofibrate treatment opposed the development of obesity, hypertriglyceridemia, and insulin resistance. However, these effects were unaffected by D2 genotype. We concluded that D2 can modulate genomic responses to fibrates, but that these effects are not sufficiently robust to alter the effects of fibrates on diet-induced obesity phenotypes. PMID:25123288

  2. Small-Scale Purification of Peroxisomes for Analytical Applications.

    PubMed

    Cramer, Jana; Effelsberg, Daniel; Girzalsky, Wolfgang; Erdmann, Ralf

    2015-09-01

    This protocol describes the isolation of peroxisomes from Saccharomyces cerevisiae by density gradient centrifugation using a sucrose, OptiPrep, or OptiPrep/sucrose gradient. Oleic acid-induced cells are first converted to spheroplasts using lyticase for cell wall digestion. Spheroplasts are homogenized, and nuclei and cell debris are removed by low-speed centrifugation to produce a postnuclear supernatant (PNS). Separation of the PNS by density gradient centrifugation is suitable for many analytical applications; however, to increase the yield of peroxisomes, further fractionation of the PNS is possible. Differential centrifugation of the PNS allows removal of the cytosol and other contaminating organelles, resulting in an organellar pellet (OP) enriched in peroxisomes and mitochondria that can be loaded onto the density gradient. Following density gradient centrifugation of the PNS or OP, fractions are collected from the bottom of the centrifuge tube. The distribution of organelles, including peroxisome peak fractions, is characterized by measurement of marker enzyme activity.

  3. Inhibitors

    MedlinePlus

    ... Community Counts Blood Safety Inhibitors Articles & Key Findings Free Materials Videos Starting the Conversation Playing it Safe A Look at Hemophilia Joint Range of Motion My Story Links to Other Websites ...

  4. Protein targeting to yeast peroxisomes.

    PubMed

    van der Klei, Ida; Veenhuis, Marten

    2007-01-01

    Peroxisomes are important organelles of eukaryote cells. Although these structures are of relatively small size, they display an unprecedented functional versatility. The principles of their biogenesis and function are strongly conserved from very simple eukaryotes to humans. Peroxisome-borne proteins are synthesized in the cytosol and posttranslationally incorporated into the organelle. The protein-sorting signal for matrix proteins, peroxisomal targeting signal (PTS), and for membrane proteins (mPTS), are also conserved. Several genes involved in peroxisomal matrix protein import have been identified (PEX genes), but the details of the molecular mechanisms of this translocation process are still unclear. Here we describe procedures to study the subcellular location of peroxisomal matrix and membrane proteins in yeast and fungi. Emphasis is placed on protocols developed for the methylotrophic yeast Hansenula polymorpha, but very similar protocols can be applied for other yeast species and filamentous fungi. The described methods include cell fractionation procedures and subcellular localization studies using fluorescence microscopy and immunolabeling techniques.

  5. Proteasome inhibitors induce p53-independent apoptosis in human cancer cells.

    PubMed

    Pandit, Bulbul; Gartel, Andrei L

    2011-01-01

    Proteasome inhibitors are used against human cancer, but their mechanisms of action are not entirely understood. For example, the role of the tumor suppressor p53 is controversial. We reevaluated the role of p53 in proteasome inhibitor-induced apoptosis by using isogenic human cancer cell lines with different p53 status. We found that well-known proteasome inhibitors such as MG132 and bortezomib, as well as the recently discovered proteasome inhibitor thiostrepton, induced p53-independent apoptosis in human cancer cell lines that correlated with p53-independent induction of proapoptotic Noxa but not Puma protein. In addition, these drugs inhibited growth of several cancer cell lines independently of p53 status. Notably, thiostrepton induced more potent apoptosis in HepG2 cells with p53 knockdown than in parental cells with wild-type p53. Our data confirm that proteasome inhibitors generally induce p53-independent apoptosis in human cancer cells.

  6. Proton pump inhibitor-induced exfoliative dermatitis: A case report

    PubMed Central

    QIU, ZHIHONG; LIU, HONGTAO; HE, LIEN; MA, YINLING; SONG, HAOJING; BAI, WANJUN; YU, MEILING

    2016-01-01

    A 74-year-old female patient was admitted to hospital following a road accident with pains in the chest, abdomen, waist, back, nose, left wrist and lower limbs. After 1 week, the patient presented with gastrointestinal bleeding, and thus was treated with protein pump inhibitors (PPIs), including lansoprazole, esomeprazole and omeprazole enteric-coated tablets, in order to inhibit acid secretion and attenuate bleeding. However, the patient developed skin rashes on the chest and right lower limb and foot 28 days following treatment initiation. The skin rashes spread and ulcerated after 3 days, and were associated with tracheal mucosal injury and hemoptysis. Subsequently, treatment of the patient with PPIs was terminated, after which the tracheal hemoptysis and skin rashes markedly improved. In addition, no new skin rashes appeared following termination of the PPI treatment. In the present case, long-term treatment of an elderly patient with PPIs may have induced exfoliative dermatitis, due to hepatic ischemia, hypoxia and acute renal failure, which may have decreased the metabolism of PPIs, resulting in the accumulation of PPI metabolites. PMID:26893644

  7. Mode of action framework analysis for receptor-mediated toxicity: the Peroxisome Proliferator-Activated Receptor alpha (PPARα) as a case study

    EPA Science Inventory

    Therapeutic hypolipidemic agents and industrial chemicals that cause peroxisome proliferation and induce liver tumors in rodents activate the nuclear receptor peroxisome proliferator-activated receptor alpha (PPARα). Research has elucidated the cellular and molecular events by w...

  8. Activating PTEN by COX-2 inhibitors antagonizes radiation-induced AKT activation contributing to radiosensitization

    SciTech Connect

    Meng, Zhen; Gan, Ye-Hua

    2015-05-01

    Radiotherapy is still one of the most effective nonsurgical treatments for many tumors. However, radioresistance remains a major impediment to radiotherapy. Although COX-2 inhibitors can induce radiosensitization, the underlying mechanism is not fully understood. In this study, we showed that COX-2 selective inhibitor celecoxib enhanced the radiation-induced inhibition of cell proliferation and apoptosis in HeLa and SACC-83 cells. Treatment with celecoxib alone dephosphorylated phosphatase and tensin homolog deleted on chromosome ten (PTEN), promoted PTEN membrane translocation or activation, and correspondingly dephosphorylated or inactivated protein kinase B (AKT). By contrast, treatment with radiation alone increased PTEN phosphorylation, inhibited PTEN membrane translocation and correspondingly activated AKT in the two cell lines. However, treatment with celecoxib or another COX-2 selective inhibitor (valdecoxib) completely blocked radiation-induced increase of PTEN phosphorylation, rescued radiation-induced decrease in PTEN membrane translocation, and correspondingly inactivated AKT. Moreover, celecoxib could also upregulate PTEN protein expression by downregulating Sp1 expression, thereby leading to the activation of PTEN transcription. Our results suggested that COX-2 inhibitors could enhance radiosensitization at least partially by activating PTEN to antagonize radiation-induced AKT activation. - Highlights: • COX-2 inhibitor, celecoxib, could enhance radiosensitization. • Radiation induced PTEN inactivation (phosphorylation) and AKT activation. • COX-2 inhibitor induced PTEN expression and activation, and inactivated AKT. • COX-2 inhibitor enhanced radiosensitization through activating PTEN.

  9. Hypoxia-inducible factor 1 mediates hypoxia-induced cardiomyocyte lipid accumulation by reducing the DNA binding activity of peroxisome proliferator-activated receptor {alpha}/retinoid X receptor

    SciTech Connect

    Belanger, Adam J.; Luo Zhengyu; Vincent, Karen A.; Akita, Geoffrey Y.; Cheng, Seng H.; Gregory, Richard J.; Jiang Canwen

    2007-12-21

    In response to cellular hypoxia, cardiomyocytes adapt to consume less oxygen by shifting ATP production from mitochondrial fatty acid {beta}-oxidation to glycolysis. The transcriptional activation of glucose transporters and glycolytic enzymes by hypoxia is mediated by hypoxia-inducible factor 1 (HIF-1). In this study, we examined whether HIF-1 was involved in the suppression of mitochondrial fatty acid {beta}-oxidation in hypoxic cardiomyocytes. We showed that either hypoxia or adenovirus-mediated expression of a constitutively stable hybrid form (HIF-1{alpha}/VP16) suppressed mitochondrial fatty acid metabolism, as indicated by an accumulation of intracellular neutral lipid. Both treatments also reduced the mRNA levels of muscle carnitine palmitoyltransferase I which catalyzes the rate-limiting step in the mitochondrial import of fatty acids for {beta}-oxidation. Furthermore, adenovirus-mediated expression of HIF-1{alpha}/VP16 in cardiomyocytes under normoxic conditions also mimicked the reduction in the DNA binding activity of peroxisome proliferator-activated receptor {alpha} (PPAR{alpha})/retinoid X receptor (RXR), in the presence or absence of a PPAR{alpha} ligand. These results suggest that HIF-1 may be involved in hypoxia-induced suppression of fatty acid metabolism in cardiomyocytes by reducing the DNA binding activity of PPAR{alpha}/RXR.

  10. Peroxisomes in Different Skeletal Cell Types during Intramembranous and Endochondral Ossification and Their Regulation during Osteoblast Differentiation by Distinct Peroxisome Proliferator-Activated Receptors.

    PubMed

    Qian, Guofeng; Fan, Wei; Ahlemeyer, Barbara; Karnati, Srikanth; Baumgart-Vogt, Eveline

    2015-01-01

    Ossification defects leading to craniofacial dysmorphism or rhizomelia are typical phenotypes in patients and corresponding knockout mouse models with distinct peroxisomal disorders. Despite these obvious skeletal pathologies, to date no careful analysis exists on the distribution and function of peroxisomes in skeletal tissues and their alterations during ossification. Therefore, we analyzed the peroxisomal compartment in different cell types of mouse cartilage and bone as well as in primary cultures of calvarial osteoblasts. The peroxisome number and metabolism strongly increased in chondrocytes during endochondral ossification from the reserve to the hypertrophic zone, whereas in bone, metabolically active osteoblasts contained a higher numerical abundance of this organelle than osteocytes. The high abundance of peroxisomes in these skeletal cell types is reflected by high levels of Pex11β gene expression. During culture, calvarial pre-osteoblasts differentiated into secretory osteoblasts accompanied by peroxisome proliferation and increased levels of peroxisomal genes and proteins. Since many peroxisomal genes contain a PPAR-responsive element, we analyzed the gene expression of PPARɑ/ß/ɣ in calvarial osteoblasts and MC3T3-E1 cells, revealing higher levels for PPARß than for PPARɑ and PPARɣ. Treatment with different PPAR agonists and antagonists not only changed the peroxisomal compartment and associated gene expression, but also induced complex alterations of the gene expression patterns of the other PPAR family members. Studies in M3CT3-E1 cells showed that the PPARß agonist GW0742 activated the PPRE-mediated luciferase expression and up-regulated peroxisomal gene transcription (Pex11, Pex13, Pex14, Acox1 and Cat), whereas the PPARß antagonist GSK0660 led to repression of the PPRE and a decrease of the corresponding mRNA levels. In the same way, treatment of calvarial osteoblasts with GW0742 increased in peroxisome number and related gene expression

  11. Phosphatidylinositol 3-kinase inhibitor(LY294002) induces apoptosis of human nasopharyngeal carcinoma in vitro and in vivo

    PubMed Central

    2010-01-01

    Background To evaluate whether PI3K/Akt pathway could effect on apoptosis and its mechanism in nasopharyngeal carcinoma cells. Methods The activation of the PI3K/Akt and its effect on CNE-2Z cells in vivo and in vitro was investigated by MTT assay, flow cytometry, western blot, ELISA, terminal deoxyribonucleotide transferase-mediated nick-end labeling assays (TUNEL), and immunohistochemical analyses, using PI3K inhibitor, LY294002. Results The results showed that LY294002 inhibited the phosphorylating of Akt (S473), cell proliferation, and induced apoptosis in CNE-2Z cells. However, our experiment results also demonstrated that apoptosis-induced LY294002 was directly regulated by caspase-9 activation pathway. Conclusion These data suggested that PI3K inhibitor, LY294002, induced apoptosis by caspase-9 activation pathway and might be as a potentially useful target for therapeutic intervention in nasopharyngeal carcinoma patients. PMID:20412566

  12. Small GTPases in peroxisome dynamics.

    PubMed

    Just, Wilhelm W; Peränen, Johan

    2016-05-01

    In this review article, we summarize current knowledge on peroxisome biogenesis/functions and the role that small GTPases may play in these processes. Precise intracellular distribution of cell organelles requires their regulated association to microtubules and the actin cytoskeleton. In this respect, RhoGDP/RhoGTP favor binding of peroxisomes to microtubules and actin filaments. In its GTP-bound form, RhoA activates a regulatory cascade involving Rho kinaseII and non-muscle myosinIIA. Such interactions frequently depend on phosphoinositides (PIs) of which PI4P, PI(4,5)P2, and PI(3,5)P2 were found to be present in the peroxisomal membrane. PIs are pivotal determinants of intracellular signaling and known to regulate a wide range of cellular functions. In many of these functions, small GTPases are implicated. The small GTPase ADP-ribosylation factor 1 (Arf1), for example, is known to stimulate synthesis of PI4P and PI(4,5)P2 on the Golgi to regulate protein and lipid sorting. In vitro binding assays localized Arf1 and the COPI complex to peroxisomes. In light of the recent discussion of pre-peroxisomal vesicle generation at the ER, peroxisomal Arf1-COPI vesicles may serve retrograde transport of ER-resident components. A mass spectrometric screen localized various Rab proteins to peroxisomes. Overexpression of these proteins in combination with laser-scanning fluorescence microscopy co-localized Rab6, Rab8, Rab10, Rab14, and Rab18 with peroxisomal structures. By analogy to the role these proteins play in other organelle dynamics, we may envisage what the function of these proteins may be in relation to the peroxisomal compartment.

  13. Human disorders of peroxisome metabolism and biogenesis.

    PubMed

    Waterham, Hans R; Ferdinandusse, Sacha; Wanders, Ronald J A

    2016-05-01

    Peroxisomes are dynamic organelles that play an essential role in a variety of cellular catabolic and anabolic metabolic pathways, including fatty acid alpha- and beta-oxidation, and plasmalogen and bile acid synthesis. Defects in genes encoding peroxisomal proteins can result in a large variety of peroxisomal disorders either affecting specific metabolic pathways, i.e., the single peroxisomal enzyme deficiencies, or causing a generalized defect in function and assembly of peroxisomes, i.e., peroxisome biogenesis disorders. In this review, we discuss the clinical, biochemical, and genetic aspects of all human peroxisomal disorders currently known.

  14. Human disorders of peroxisome metabolism and biogenesis.

    PubMed

    Waterham, Hans R; Ferdinandusse, Sacha; Wanders, Ronald J A

    2016-05-01

    Peroxisomes are dynamic organelles that play an essential role in a variety of cellular catabolic and anabolic metabolic pathways, including fatty acid alpha- and beta-oxidation, and plasmalogen and bile acid synthesis. Defects in genes encoding peroxisomal proteins can result in a large variety of peroxisomal disorders either affecting specific metabolic pathways, i.e., the single peroxisomal enzyme deficiencies, or causing a generalized defect in function and assembly of peroxisomes, i.e., peroxisome biogenesis disorders. In this review, we discuss the clinical, biochemical, and genetic aspects of all human peroxisomal disorders currently known. PMID:26611709

  15. Proteasome inhibitors induce apoptosis of prostate cancer cells by inducing nuclear translocation of IkappaBalpha.

    PubMed

    Vu, Hai-Yen; Juvekar, Ashish; Ghosh, Chandra; Ramaswami, Sitharam; Le, Dung Hong; Vancurova, Ivana

    2008-07-15

    Proteasome inhibitors are known to suppress the proteasome-mediated degradation of IkappaBalpha in stimulated cells. This results in the cytoplasmic retention of NFkappaB and its reduced nuclear transcriptional activity. In this study, we show that in the metastatic prostate cancer cells, the proteasome inhibitors exhibit a novel, previously unrecognized effect: they increase the cellular levels of IkappaBalpha, which then translocates to the nucleus, associates with the nuclear p65 NFkappaB, thus inhibiting the constitutive NFkappaB DNA binding activity and inducing apoptosis. The proteasome inhibition-induced nuclear translocation of IkappaBalpha is dependent on de novo protein synthesis, occurs also in other cell types, and does not require IkappaBalpha phosphorylation on Ser-32. Since NFkappaB activity is constitutively increased in many human cancers as well as in inflammatory disorders, the proteasome inhibition-induced nuclear translocation of IkappaBalpha could thus provide a new therapeutic strategy aimed at the specific inhibition of NFkappaB activity by the nuclear IkappaBalpha.

  16. Evaluation of aspirin metabolites as inhibitors of hypoxia-inducible factor hydroxylases.

    PubMed

    Lienard, Benoit M; Conejo-García, Ana; Stolze, Ineke; Loenarz, Christoph; Oldham, Neil J; Ratcliffe, Peter J; Schofield, Christopher J

    2008-12-21

    Known and potential aspirin metabolites were evaluated as inhibitors of oxygen-sensing hypoxia-inducible transcription factor (HIF) hydroxylases; some of the metabolites were found to stabilise HIF-alpha in cells. PMID:19048166

  17. Hypoxia-inducible factor-1α in vascular smooth muscle regulates blood pressure homeostasis through a peroxisome proliferator-activated receptor-γ-angiotensin II receptor type 1 axis.

    PubMed

    Huang, Yan; Di Lorenzo, Annarita; Jiang, Weidong; Cantalupo, Anna; Sessa, William C; Giordano, Frank J

    2013-09-01

    Hypertension is a major worldwide health issue for which only a small proportion of cases have a known mechanistic pathogenesis. Of the defined causes, none have been directly linked to heightened vasoconstrictor responsiveness, despite the fact that vasomotor tone in resistance vessels is a fundamental determinant of blood pressure. Here, we reported a previously undescribed role for smooth muscle hypoxia-inducible factor-1α (HIF-1α) in controlling blood pressure homeostasis. The lack of HIF-1α in smooth muscle caused hypertension in vivo and hyperresponsiveness of resistance vessels to angiotensin II stimulation ex vivo. These data correlated with an increased expression of angiotensin II receptor type I in the vasculature. Specifically, we show that HIF-1α, through peroxisome proliferator-activated receptor-γ, reciprocally defined angiotensin II receptor type I levels in the vessel wall. Indeed, pharmacological blockade of angiotensin II receptor type I by telmisartan abolished the hypertensive phenotype in smooth muscle cell-HIF-1α-KO mice. These data revealed a determinant role of a smooth muscle HIF-1α/peroxisome proliferator-activated receptor-γ/angiotensin II receptor type I axis in controlling vasomotor responsiveness and highlighted an important pathway, the alterations of which may be critical in a variety of hypertensive-based clinical settings. PMID:23918749

  18. Selective heterocyclic amidine inhibitors of human inducible nitric oxide synthase.

    PubMed

    Moormann, A E; Metz, S; Toth, M V; Moore, W M; Jerome, G; Kornmeier, C; Manning, P; Hansen, D W; Pitzele, B S; Webber, R K

    2001-10-01

    The potency and selectivity of a series of 5-hetero-2-iminohexahydroazepines were examined as inhibitors of the three human NOS isoforms. The effect of ring substitution of the 5-carbon for a heteroatom is presented. Potencies (IC(50)'s) for these inhibitors are in the low micromolar range for hi-NOS with some examples exhibiting a 500x selectivity versus hec-NOS.

  19. Agonist-induced activation releases peroxisome proliferator-activated receptor beta/delta from its inhibition by palmitate-induced nuclear factor-kappaB in skeletal muscle cells.

    PubMed

    Jové, Mireia; Laguna, Juan C; Vázquez-Carrera, Manuel

    2005-05-01

    The mechanisms by which elevated levels of free fatty acids cause insulin resistance are not well understood, but there is a strong correlation between insulin resistance and intramyocellular lipid accumulation in skeletal muscle. In addition, accumulating evidence suggests a link between inflammation and type 2 diabetes. The aim of this work was to study whether the exposure of skeletal muscle cells to palmitate affected peroxisome proliferator-activated receptor (PPAR) beta/delta activity. Here, we report that exposure of C2C12 skeletal muscle cells to 0.75 mM palmitate reduced (74%, P<0.01) the mRNA levels of the PPARbeta/delta-target gene pyruvatedehydrogenase kinase 4 (PDK-4), which is involved in fatty acid utilization. This reduction was not observed in the presence of the PPARbeta/delta agonist L-165041. This drug prevented palmitate-induced nuclear factor (NF)-kappaB activation. Increased NF-kappaB activity after palmitate exposure was associated with enhanced protein-protein interaction between PPARbeta/delta and p65. Interestingly, treatment with the PPARbeta/delta agonist L-165041 completely abolished this interaction. These results indicate that palmitate may reduce fatty acid utilization in skeletal muscle cells by reducing PPARbeta/delta signaling through increased NF-kappaB activity.

  20. Arsenic toxicity induced endothelial dysfunction and dementia: Pharmacological interdiction by histone deacetylase and inducible nitric oxide synthase inhibitors

    SciTech Connect

    Sharma, Bhupesh Sharma, P.M.

    2013-11-15

    Arsenic toxicity has been reported to damage all the major organs including the brain and vasculature. Dementia including Alzheimer's disease (AD) and vascular dementia (VaD) are posing greater risk to the world population as it is now increasing at a faster rate. We have investigated the role of sodium butyrate, a selective histone deacetylase (HDAC) inhibitor and aminoguanidine, a selective inducible nitric oxide synthase (iNOS) inhibitor in pharmacological interdiction of arsenic toxicity induced vascular endothelial dysfunction and dementia in rats. Arsenic toxicity was done by administering arsenic drinking water to rats. Morris water-maze (MWM) test was used for assessment of learning and memory. Endothelial function was assessed using student physiograph. Oxidative stress (aortic superoxide anion, serum and brain thiobarbituric acid reactive species, brain glutathione) and nitric oxide levels (serum nitrite/nitrate) were also measured. Arsenic treated rats have shown impairment of endothelial function, learning and memory, reduction in serum nitrite/nitrate and brain GSH levels along with increase in serum and brain TBARS. Sodium butyrate as well as aminoguanidine significantly convalesce arsenic induced impairment of learning, memory, endothelial function, and alterations in various biochemical parameters. It may be concluded that arsenic induces endothelial dysfunction and dementia, whereas, sodium butyrate, a HDAC inhibitor as well as aminoguanidine, a selective iNOS inhibitor may be considered as potential agents for the management of arsenic induced endothelial dysfunction and dementia. - Highlights: • As has induced endothelial dysfunction (Edf) and vascular dementia (VaD). • As has increased oxidative stress, AChE activity and decreased serum NO. • Inhibitors of HDAC and iNOS have attenuated As induced Edf and VaD. • Both the inhibitors have attenuated As induced biochemical changes. • Inhibitor of HDAC and iNOS has shown good potential in

  1. NFκB inhibitors induce cell death in glioblastomas.

    PubMed

    Zanotto-Filho, Alfeu; Braganhol, Elizandra; Schröder, Rafael; de Souza, Luís Henrique T; Dalmolin, Rodrigo J S; Pasquali, Matheus A Bittencourt; Gelain, Daniel Pens; Battastini, Ana Maria Oliveira; Moreira, José Cláudio Fonseca

    2011-02-01

    Identification of novel target pathways in glioblastoma (GBM) remains critical due to poor prognosis, inefficient therapies and recurrence associated with these tumors. In this work, we evaluated the role of nuclear-factor-kappa-B (NFκB) in the growth of GBM cells, and the potential of NFκB inhibitors as antiglioma agents. NFκB pathway was found overstimulated in GBM cell lines and in tumor specimens compared to normal astrocytes and healthy brain tissues, respectively. Treatment of a panel of established GBM cell lines (U138MG, U87, U373 and C6) with pharmacological NFκB inhibitors (BAY117082, parthenolide, MG132, curcumin and arsenic trioxide) and NFκB-p65 siRNA markedly decreased the viability of GBMs as compared to inhibitors of other signaling pathways such as MAPKs (ERK, JNK and p38), PKC, EGFR and PI3K/Akt. In addition, NFκB inhibitors presented a low toxicity to normal astrocytes, indicating selectivity to cancerous cells. In GBMs, mitochondrial dysfunction (membrane depolarization, bcl-xL downregulation and cytochrome c release) and arrest in the G2/M phase were observed at the early steps of NFκB inhibitors treatment. These events preceded sub-G1 detection, apoptotic body formation and caspase-3 activation. Also, NFκB was found overstimulated in cisplatin-resistant C6 cells, and treatment of GBMs with NFκB inhibitors overcame cisplatin resistance besides potentiating the effects of the chemotherapeutics, cisplatin and doxorubicin. These findings support NFκB as a potential target to cell death induction in GBMs, and that the NFκB inhibitors may be considered for in vivo testing on animal models and possibly on GBM therapy.

  2. Resistance to BRAF inhibitors induces glutamine dependency in melanoma cells

    PubMed Central

    Baenke, Franziska; Chaneton, Barbara; Smith, Matthew; Van Den Broek, Niels; Hogan, Kate; Tang, Haoran; Viros, Amaya; Martin, Matthew; Galbraith, Laura; Girotti, Maria R.; Dhomen, Nathalie; Gottlieb, Eyal; Marais, Richard

    2016-01-01

    BRAF inhibitors can extend progression-free and overall survival in melanoma patients whose tumors harbor mutations in BRAF. However, the majority of patients eventually develop resistance to these drugs. Here we show that BRAF mutant melanoma cells that have developed acquired resistance to BRAF inhibitors display increased oxidative metabolism and increased dependency on mitochondria for survival. Intriguingly, the increased oxidative metabolism is associated with a switch from glucose to glutamine metabolism and an increased dependence on glutamine over glucose for proliferation. We show that the resistant cells are more sensitive to mitochondrial poisons and to inhibitors of glutaminolysis, suggesting that targeting specific metabolic pathways may offer exciting therapeutic opportunities to treat resistant tumors, or to delay emergence of resistance in the first-line setting. PMID:26365896

  3. The role of peroxisomes in the integration of metabolism and evolutionary diversity of photosynthetic organisms.

    PubMed

    Igamberdiev, Abir U; Lea, Peter J

    2002-08-01

    The peroxisome is a metabolic compartment serving for the rapid oxidation of substrates, a process that is not coupled to energy conservation. In plants and algae, peroxisomes connect biosynthetic and oxidative metabolic routes and compartmentalize potentially lethal steps of metabolism such as the formation of reactive oxygen species and glyoxylate, thus preventing poisoning of the cell and futile recycling. Peroxisomes exhibit properties resembling inside-out vesicles and possess special systems for the import of specific proteins, which form multi-enzyme complexes (metabolons) linking numerous reactions to flavin-dependent oxidation, coupled to the decomposition of hydrogen peroxide by catalase. Hydrogen peroxide and superoxide originating in peroxisomes are important mediators in signal transduction pathways, particularly those involving salicylic acid. By contributing to the synthesis of oxalate, formate and other organic acids, peroxisomes regulate major fluxes of primary and secondary metabolism. The evolutionary diversity of algae has led to the presence of a wide range of enzymes in the peroxisomes that are only similar to higher plants in their direct predecessors, the Charophyceae. The appearance of seed plants was connected to the acquirement by storage tissues, of a peroxisomal fatty acid oxidation function linked to the glyoxylate cycle, which is induced during seed germination and maturation. Rearrangement of the peroxisomal photorespiratory function between different tissues of higher plants led to the appearance of different types of photosynthetic metabolism. The peroxisome may therefore have played a key role in the evolutionary formation of metabolic networks, via establishing interconnections between different metabolic compartments.

  4. Reevaluation of the role of Pex1 and dynamin-related proteins in peroxisome membrane biogenesis

    PubMed Central

    Motley, Alison M.; Galvin, Paul C.; Ekal, Lakhan; Nuttall, James M.

    2015-01-01

    A recent model for peroxisome biogenesis postulates that peroxisomes form de novo continuously in wild-type cells by heterotypic fusion of endoplasmic reticulum–derived vesicles containing distinct sets of peroxisomal membrane proteins. This model proposes a role in vesicle fusion for the Pex1/Pex6 complex, which has an established role in matrix protein import. The growth and division model proposes that peroxisomes derive from existing peroxisomes. We tested these models by reexamining the role of Pex1/Pex6 and dynamin-related proteins in peroxisome biogenesis. We found that induced depletion of Pex1 blocks the import of matrix proteins but does not affect membrane protein delivery to peroxisomes; markers for the previously reported distinct vesicles colocalize in pex1 and pex6 cells; peroxisomes undergo continued growth if fission is blocked. Our data are compatible with the established primary role of the Pex1/Pex6 complex in matrix protein import and show that peroxisomes in Saccharomyces cerevisiae multiply mainly by growth and division. PMID:26644516

  5. Hif-2α promotes degradation of mammalian peroxisomes by selective autophagy.

    PubMed

    Walter, Katharina M; Schönenberger, Miriam J; Trötzmüller, Martin; Horn, Michael; Elsässer, Hans-Peter; Moser, Ann B; Lucas, Miriam S; Schwarz, Tobias; Gerber, Philipp A; Faust, Phyllis L; Moch, Holger; Köfeler, Harald C; Krek, Wilhelm; Kovacs, Werner J

    2014-11-01

    Peroxisomes play a central role in lipid metabolism, and their function depends on molecular oxygen. Low oxygen tension or von Hippel-Lindau (Vhl) tumor suppressor loss is known to stabilize hypoxia-inducible factors alpha (Hif-1α and Hif-2α) to mediate adaptive responses, but it remains unknown if peroxisome homeostasis and metabolism are interconnected with Hif-α signaling. By studying liver-specific Vhl, Vhl/Hif1α, and Vhl/Hif2α knockout mice, we demonstrate a regulatory function of Hif-2α signaling on peroxisomes. Hif-2α activation augments peroxisome turnover by selective autophagy (pexophagy) and thereby changes lipid composition reminiscent of peroxisomal disorders. The autophagy receptor Nbr1 localizes to peroxisomes and is likewise degraded by Hif-2α-mediated pexophagy. Furthermore, we demonstrate that peroxisome abundance is reduced in VHL-deficient human clear cell renal cell carcinomas with high HIF-2α levels. These results establish Hif-2α as a negative regulator of peroxisome abundance and metabolism and suggest a mechanism by which cells attune peroxisomal function with oxygen availability.

  6. Reevaluation of the role of Pex1 and dynamin-related proteins in peroxisome membrane biogenesis.

    PubMed

    Motley, Alison M; Galvin, Paul C; Ekal, Lakhan; Nuttall, James M; Hettema, Ewald H

    2015-12-01

    A recent model for peroxisome biogenesis postulates that peroxisomes form de novo continuously in wild-type cells by heterotypic fusion of endoplasmic reticulum-derived vesicles containing distinct sets of peroxisomal membrane proteins. This model proposes a role in vesicle fusion for the Pex1/Pex6 complex, which has an established role in matrix protein import. The growth and division model proposes that peroxisomes derive from existing peroxisomes. We tested these models by reexamining the role of Pex1/Pex6 and dynamin-related proteins in peroxisome biogenesis. We found that induced depletion of Pex1 blocks the import of matrix proteins but does not affect membrane protein delivery to peroxisomes; markers for the previously reported distinct vesicles colocalize in pex1 and pex6 cells; peroxisomes undergo continued growth if fission is blocked. Our data are compatible with the established primary role of the Pex1/Pex6 complex in matrix protein import and show that peroxisomes in Saccharomyces cerevisiae multiply mainly by growth and division.

  7. Salicylic Acid Inhibits Synthesis of Proteinase Inhibitors in Tomato Leaves Induced by Systemin and Jasmonic Acid.

    PubMed Central

    Doares, S. H.; Narvaez-Vasquez, J.; Conconi, A.; Ryan, C. A.

    1995-01-01

    Salicylic acid (SA) and acetylsalicylic acid (ASA), previously shown to inhibit proteinase inhibitor synthesis induced by wounding, oligouronides (H.M. Doherty, R.R. Selvendran, D.J. Bowles [1988] Physiol Mol Plant Pathol 33: 377-384), and linolenic acid (H. Pena-Cortes, T. Albrecht, S. Prat, E.W. Weiler, L. Willmitzer [1993] Planta 191: 123-128), are shown here to be potent inhibitors of systemin-induced and jasmonic acid (JA)-induced synthesis of proteinase inhibitor mRNAs and proteins. The inhibition by SA and ASA of proteinase inhibitor synthesis induced by systemin and JA, as well as by wounding and oligosaccharide elicitors, provides further evidence that both oligosaccharide and polypeptide inducer molecules utilize the octadecanoid pathway to signal the activation of proteinase inhibitor genes. Tomato (Lycopersicon esculentum) leaves were pulse labeled with [35S]methionine, followed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis, and the inhibitory effects of SA are shown to be specific for the synthesis of a small number of JA-inducible proteins that includes the proteinase inhibitors. Previous results have shown that SA inhibits the conversion of 13S-hydroperoxy linolenic acid to 12-oxo-phytodienoic acid, thereby inhibiting the signaling pathway by blocking synthesis of JA. Here we report that the inhibition of synthesis of proteinase inhibitor proteins and mRNAs by SA in both light and darkness also occurs at a step in the signal transduction pathway, after JA synthesis but preceding transcription of the inhibitor genes. PMID:12228577

  8. The Pichia pastoris PER6 gene product is a peroxisomal integral membrane protein essential for peroxisome biogenesis and has sequence similarity to the Zellweger syndrome protein PAF-1.

    PubMed Central

    Waterham, H R; de Vries, Y; Russel, K A; Xie, W; Veenhuis, M; Cregg, J M

    1996-01-01

    We report the cloning of PER6, a gene essential for peroxisome biogenesis in the methylotrophic yeast Pichia pastoris. The PER6 sequence predicts that its product Per6p is a 52-kDa polypeptide with the cysteine-rich C3HC4 motif. Per6p has significant overall sequence similarity with the human peroxisome assembly factor PAF-1, a protein that is defective in certain patients suffering from the peroxisomal disorder Zellweger syndrome, and with car1, a protein required for peroxisome biogenesis and caryogamy in the filamentous fungus Podospora anserina. In addition, the C3HC4 motif and two of the three membrane-spanning segments predicted for Per6p align with the C3HC4 motifs and the two membrane-spanning segments predicted for PAF-1 and car1. Like PAF-1, Per6p is a peroxisomal integral membrane protein. In methanol- or oleic acid-induced cells of per6 mutants, morphologically recognizable peroxisomes are absent. Instead, peroxisomal remnants are observed. In addition, peroxisomal matrix proteins are synthesized but located in the cytosol. The similarities between Per6p and PAF-1 in amino acid sequence and biochemical properties, and between mutants defective in their respective genes, suggest that Per6p is the putative yeast homolog of PAF-1. PMID:8628321

  9. Peroxisome proliferation, wound-activated responses and expression of peroxisome-associated genes are cross-regulated but uncoupled in Arabidopsis thaliana.

    PubMed

    Castillo, Mari Cruz; Sandalio, Luisa María; Del Río, Luís Alfonso; León, José

    2008-04-01

    Plant peroxisomes are multifunctional organelles that show plasticity in number, size, morphology, cellular location and metabolic functions. Many of these changes occur in response to environmental factors and are decisive for the development and defence of the plant. Among them, peroxisomal beta-oxidation-mediated synthesis of jasmonic acid (JA) is a key process in regulating development as well as wound- or pathogen-triggered defence responses. This work seeks for the connection between wound, JA and the proliferation of peroxisomes in Arabidopsis thaliana. The hypolipidemic drug clofibrate (CFB) induced the proliferation of peroxisomes and the expression of the beta-oxidation 3-ketoacyl-CoA thiolase 2 (KAT2) gene, coding for a key enzyme in the biosynthesis of JA, among other wound- and JA-responsive gene transcripts in Arabidopsis leaves. The CFB-activated expression of wound-responsive genes was not dependent on JA synthesis or perception and those responsive to JA required the function of the F-box protein COI1. In turn, wounding neither triggered peroxisome proliferation nor required peroxisome integrity to activate gene expression. Interestingly, cells from JA-treated leaves contained fewer but larger peroxisomes than cells from untreated leaves. The proliferation of peroxisomes, the synthesis of JA and the activation of wound-responsive genes by CFB, although functionally connected, were uncoupled in Arabidopsis.

  10. Peroxisome homeostasis: Mechanisms of division and selective degradation of peroxisomes in mammals.

    PubMed

    Honsho, Masanori; Yamashita, Shun-ichi; Fujiki, Yukio

    2016-05-01

    Peroxisome number and quality are maintained by its biogenesis and turnover and are important for the homeostasis of peroxisomes. Peroxisomes are increased in number by division with dynamic morphological changes including elongation, constriction, and fission. In the course of peroxisomal division, peroxisomal morphogenesis is orchestrated by Pex11β, dynamin-like protein 1 (DLP1), and mitochondrial fission factor (Mff). Conversely, peroxisome number is reduced by its degradation. Peroxisomes are mainly degraded by pexophagy, a type of autophagy specific for peroxisomes. Upon pexophagy, an adaptor protein translocates on peroxisomal membrane and connects peroxisomes to autophagic machineries. Molecular mechanisms of pexophagy are well studied in yeast systems where several specific adaptor proteins are identified. Pexophagy in mammals also proceeds in a manner dependent on adaptor proteins. In this review, we address the recent progress in studies on peroxisome morphogenesis and pexophagy.

  11. Multiple Pathways for Protein Transport to Peroxisomes

    PubMed Central

    Kim, P.K.; Hettema, E.H.

    2015-01-01

    Peroxisomes are unique among the organelles of the endomembrane system. Unlike other organelles that derive most if not all of their proteins from the ER (endoplasmic reticulum), peroxisomes contain dedicated machineries for import of matrix proteins and insertion of membrane proteins. However, peroxisomes are also able to import a subset of their membrane proteins from the ER. One aspect of peroxisome biology that has remained ill defined is the role the various import pathways play in peroxisome maintenance. In this review, we discuss the available data on matrix and membrane protein import into peroxisomes. PMID:25681696

  12. Multiple pathways for protein transport to peroxisomes.

    PubMed

    Kim, P K; Hettema, E H

    2015-03-27

    Peroxisomes are unique among the organelles of the endomembrane system. Unlike other organelles that derive most if not all of their proteins from the ER (endoplasmic reticulum), peroxisomes contain dedicated machineries for import of matrix proteins and insertion of membrane proteins. However, peroxisomes are also able to import a subset of their membrane proteins from the ER. One aspect of peroxisome biology that has remained ill defined is the role the various import pathways play in peroxisome maintenance. In this review, we discuss the available data on matrix and membrane protein import into peroxisomes.

  13. DPP IV inhibitor blocks mescaline-induced scratching and amphetamine-induced hyperactivity in mice.

    PubMed

    Lautar, Susan L; Rojas, Camilo; Slusher, Barbara S; Wozniak, Krystyna M; Wu, Ying; Thomas, Ajit G; Waldon, Daniel; Li, William; Ferraris, Dana; Belyakov, Sergei

    2005-06-28

    Dipeptidyl peptidase IV (DPP IV) is a ubiquitous membrane-bound enzyme that cleaves the two N-terminal amino acids from peptides with a proline or alanine residue in the second position from the amino end. Potential substrates for DPP IV include several neuropeptides, suggesting a role for DPP IV in neurological processes. We have developed a potent DPP IV inhibitor (IC50 = 30 nM), 1-(2-amino-3-methyl-butyryl)-azetidine-2-carbonitrile (AMAC), which has shown efficacy in two established models of psychosis: mescaline-induced scratching and amphetamine-induced hyperactivity. In the mescaline-induced scratching model, AMAC treatment before mescaline administration reduced the number of scratching paroxysms by 68% (P < 0.01). The compound showed a dose-dependent effect, inhibiting significantly at 6, 20 and 60 mg/kg (37%, 39% and 68%, respectively). In the amphetamine-induced hyperactivity model, 50 and 60 mg/kg AMAC, given before injection of amphetamine, significantly reduced hyper-locomotion by 65% and 76%, respectively. Additionally, AMAC showed no significant activity in binding assays for 20 receptors thought to be involved in the pathology of schizophrenia, including dopamine, serotonin and glutamate. A structurally similar analog, 1-(2-dimethylamino-3-methyl-butyryl)-azetidine-2-carbonitrile (DAMAC), that does not inhibit DPP IV, was inactive in both models. Taken together, these data suggest that the antipsychotic effects of AMAC are the result of DPP IV inhibition.

  14. Proteasome inhibitors induce apoptosis and reduce viral replication in primary effusion lymphoma cells.

    PubMed

    Saji, Chiaki; Higashi, Chizuka; Niinaka, Yasufumi; Yamada, Koji; Noguchi, Kohji; Fujimuro, Masahiro

    2011-12-01

    Primary effusion lymphoma (PEL) is an aggressive neoplasm caused by Kaposi's sarcoma-associated herpesvirus (KSHV). This study provides evidence that proteasomal activity is required for both survival of PEL cells stably harboring the KSHV genome and viral replication of KSHV. We evaluated the cytotoxic effects of proteasome inhibitors on PEL cells. The proteasome inhibitors MG132, lactacystin, and proteasome inhibitor I dramatically inhibited cell proliferation and induced apoptosis of PEL cells through the accumulation of p21 and p27. Furthermore, proteasome inhibitors induced the stabilization of NF-κB inhibitory molecule (IκBα) and suppressed the transcriptional activity of NF-κB in PEL cells. The NF-κB specific inhibitor BAY11-7082 also induced apoptosis in PEL cells. The constitutive activation of NF-κB signaling is essential for the survival and growth of B cell lymphoma cells, including PEL cells. NF-κB signaling is upregulated by proteasome-dependent degradation of IκBα. The suppression of NF-κB signaling by proteasome inhibitors may contribute to the induction of apoptosis in PEL cells. In addition, proteasome activity is required for KSHV replication in KSHV latently infected PEL cells. MG132 reduced the production of progeny virus from PEL cells at low concentrations, which do not affect PEL cell growth. These findings suggest that proteasome inhibitors may represent a novel strategy for the treatment of KSHV infection and KSHV-associated lymphomas.

  15. Specific MAPK inhibitors prevent hyperglycemia-induced renal diseases in type 1 diabetic mouse model.

    PubMed

    Hong, Zhe; Hong, Zongyuan; Wu, Denglong; Nie, Hezhongrong

    2016-08-01

    Mitogen-activated protein kinase (MAPK) and renin-angiotensin system (RAS) play critical roles in the process of renal diseases, but their interaction has not been comprehensively discussed. In the present studies, we investigated the renoprotective effects of MPAK inhibitors on renal diseases in type 1 diabetic mouse model, and clarify the crosstalk among MAPK signaling. Type 1 diabetic mouse model was established in male C57BL/6 J mice, and treated with or without 10 mg/kg MAPK blockers, including ERK inhibitor PD98059, p38 inhibitor SB203850, and JNK inhibitor SP600125 for four weeks. Hyperglycemia induced renal injuries, but treating them with MAPK inhibitors significantly decreased glomerular volume and glycogen in renal tissues. Although slightly changed body weight and fasting blood glucose levels, MAPK inhibitors attenuated blood urea nitrogen, urea protein, and microalbuminuria. Administration also reduced the diabetes-induced RAS activation, including angiotensin II converting enzyme (c) and Ang II, which contributed to its renal protective effects in the diabetic mice. In addition, the anti-RAS of MAPK inhibitor treatment markedly reduced gene expression of tumor necrosis factor-α, interleukin-6, and inducible nitric oxide synthase, fibrotic accumulation, and transforming growth factor-β1 levels in renal tissues. Furthermore, chemical inhibitors and genetic siRNA results identified the crosstalk among the three MAPK signaling, and proved JNK signaling played a critical role in MAPK-mediated ACE pathway in hyperglycemia state. Collectively, these results support the therapeutic effects of MAPK-specific inhibitors, especially JNK inactivation, on hyperglycemia-induced renal damages. PMID:27389030

  16. Peroxisome biogenesis in mammalian cells

    PubMed Central

    Fujiki, Yukio; Okumoto, Kanji; Mukai, Satoru; Honsho, Masanori; Tamura, Shigehiko

    2014-01-01

    To investigate peroxisome assembly and human peroxisome biogenesis disorders (PBDs) such as Zellweger syndrome, thirteen different complementation groups (CGs) of Chinese hamster ovary (CHO) cell mutants defective in peroxisome biogenesis have been isolated and established as a model research system. Successful gene-cloning studies by a forward genetic approach utilized a rapid functional complementation assay of CHO cell mutants led to isolation of human peroxin (PEX) genes. Search for pathogenic genes responsible for PBDs of all 14 CGs is now completed together with the homology search by screening the human expressed sequence tag database using yeast PEX genes. Peroxins are divided into three groups: (1) peroxins including Pex3p, Pex16p, and Pex19p, are responsible for peroxisome membrane biogenesis via classes I and II pathways; (2) peroxins that function in matrix protein import; (3) those such as three forms of Pex11p, Pex11pα, Pex11pβ, and Pex11pγ, are involved in peroxisome proliferation where DLP1, Mff, and Fis1 coordinately function. In membrane assembly, Pex19p forms complexes in the cytosol with newly synthesized PMPs including Pex16p and transports them to the receptor Pex3p, whereby peroxisomal membrane is formed (Class I pathway). Pex19p likewise forms a complex with newly made Pex3p and translocates it to the Pex3p receptor, Pex16p (Class II pathway). In matrix protein import, newly synthesized proteins harboring peroxisome targeting signal type 1 or 2 are recognized by Pex5p or Pex7p in the cytoplasm and are imported to peroxisomes via translocation machinery. In regard to peroxisome-cytoplasmic shuttling of Pex5p, Pex5p initially targets to an 800-kDa docking complex consisting of Pex14p and Pex13p and then translocates to a 500-kDa RING translocation complex. At the terminal step, Pex1p and Pex6p of the AAA family mediate the export of Pex5p, where Cys-ubiquitination of Pex5p is essential for the Pex5p exit. PMID:25177298

  17. Assembly, maintenance and dynamics of peroxisomes.

    PubMed

    Erdmann, Ralf

    2016-05-01

    Peroxisomes are ubiquitous organelles of eukaryotic cells, and it is becoming increasingly clear that the biogenesis of these multi-purpose organelles is more complex than initially anticipated. Along this line, peroxisomes exhibit features, which clearly distinguish them from other cellular organelles, like their ability to import folded proteins or their capability to form de novo. However, further insight into the cellular life of peroxisomes also revealed features that they share with other organelles, such as organelle fission or regulated degradation by autophagy, that are similar for peroxisomes, mitochondria and chloroplasts. This special issue highlights recent progress in the understanding of the biogenesis of peroxisomes with emphasis on the assembly, maintenance and dynamics of the organelles. In particular, it focuses on the following areas: (i) topogenesis of peroxisomal matrix proteins as well as the structure and function of peroxisomal protein import machineries. (ii) Peroxisomal targeting of membrane proteins and de novo formation of peroxisomes. (iii) Maintenance of peroxisomes in health and disease. (iv) Proliferation and regulated degradation of peroxisomes. (v) Motility and inheritance of peroxisomes. (vi) Role of peroxisomes in the cellular context.

  18. Regulation of peroxisome dynamics by phosphorylation.

    PubMed

    Oeljeklaus, Silke; Schummer, Andreas; Mastalski, Thomas; Platta, Harald W; Warscheid, Bettina

    2016-05-01

    Peroxisomes are highly dynamic organelles that can rapidly change in size, abundance, and protein content in response to alterations in nutritional and other environmental conditions. These dynamic changes in peroxisome features, referred to as peroxisome dynamics, rely on the coordinated action of several processes of peroxisome biogenesis. Revealing the regulatory mechanisms of peroxisome dynamics is an emerging theme in cell biology. These mechanisms are inevitably linked to and synchronized with the biogenesis and degradation of peroxisomes. To date, the key players and basic principles of virtually all steps in the peroxisomal life cycle are known, but regulatory mechanisms remained largely elusive. A number of recent studies put the spotlight on reversible protein phosphorylation for the control of peroxisome dynamics and highlighted peroxisomes as hubs for cellular signal integration and regulation. Here, we will present and discuss the results of several studies performed using yeast and mammalian cells that convey a sense of the impact protein phosphorylation may have on the modulation of peroxisome dynamics by regulating peroxisomal matrix and membrane protein import, proliferation, inheritance, and degradation. We further put forward the idea to make use of current data on phosphorylation sites of peroxisomal and peroxisome-associated proteins reported in advanced large-scale phosphoproteomic studies.

  19. A Sulfhydryl Reagent Modulates Systemic Signaling for Wound-Induced and Systemin-Induced Proteinase Inhibitor Synthesis.

    PubMed Central

    Narvaez-Vasquez, J.; Orozco-Cardenas, M. L.; Ryan, C. A.

    1994-01-01

    The sulfhydryl group reagent p-chloromecuribenzene sulfonic acid (PCMBS), an established inhibitor of active apoplastic phloem loading of sucrose in several plant species, is shown to be a powerful inhibitor of wound-induced and systemin-induced activation of proteinase inhibitor synthesis and accumulation in leaves of tomato plants (Lycopersicon esculentum cv Castlemart). PCMBS, supplied to young tomato plants through their cut stems, blocks accumulation of proteinase inhibitors in leaves in response to wounding. The application of systemin directly to fresh wounds enhances systemic accumulation of proteinase inhibitors to levels higher than wounding alone. Placed on fresh wounds, PCMBS severely inhibits systemic induction of proteinase inhibitors, in both the presence and absence of exogenous systemin. PCMBS inhibition can be reversed by cysteine, dithiothreitol, and glutathione. Radiolabeled systemin placed on fresh wounds is readily transported from the wounded leaves to upper leaves. However, in the presence of PCMBS, radiolabeled systemin is not transported away from wound sites. Induction of proteinase inhibitor I synthesis by oligouronides (degree of polymerization [almost equal to] 20), linolenic acid, or methyl jasmonate was not inhibited by PCMBS. The cumulative data support a possible role for sulfhydryl groups in mediating the translocation of systemin from wound sites to distal receptor sites in tomato plants and further support a role for systemin as a systemic wound signal. PMID:12232239

  20. 5-Lipoxygenase Inhibitors Attenuate TNF-α-Induced Inflammation in Human Synovial Fibroblasts

    PubMed Central

    Lin, Han-Ching; Lin, Tzu-Hung; Wu, Ming-Yueh; Chiu, Yung-Cheng; Tang, Chih-Hsin; Hour, Mann-Jen; Liou, Houng-Chi; Tu, Huang-Ju; Yang, Rong-Sen; Fu, Wen-Mei

    2014-01-01

    The lipoxygenase isoform of 5-lipoxygenase (5-LOX) is reported to be overexpressed in human rheumatoid arthritis synovial tissue and involved in the progress of inflammatory arthritis. However, the detailed mechanism of how 5-lipoxygenase regulates the inflammatory response in arthritis synovial tissue is still unclear. The aim of this study was to investigate the involvement of lipoxygenase pathways in TNF-α-induced production of cytokines and chemokines. Human synovial fibroblasts from rheumatoid patients were used in this study. 5-LOX inhibitors and shRNA were used to examine the involvement of 5-LOX in TNF-α-induced cytokines and chemokines expression. The signaling pathways were examined by Western Blotting or immunofluorescence staining. The effect of 5-LOX inhibitor on TNF-α-induced chemokine expression and paw edema was also explored in vivo in C57BL/6 mice. Treatment with 5-LOX inhibitors significantly decreased TNF-α-induced pro-inflammatory mediators including interleukin-6 (IL-6) and monocyte chemo-attractant protein-1 (MCP-1) in human synovial fibroblasts. Knockdown of 5-LOX using shRNA exerted similar inhibitory effects. The abrogation of NF-κB activation was involved in the antagonizing effects of these inhibitors. Furthermore, 5-LOX inhibitor decreased TNF-α-induced up-regulation of serum MCP-1 level and paw edema in mouse model. Our results provide the evidence that the administration of 5-LOX inhibitors is able to ameliorate TNF-α-induced cytokine/chemokine release and paw edema, indicating that 5-LOX inhibitors may be developed for therapeutic treatment of inflammatory arthritis. PMID:25229347

  1. The peroxisome as a cell signaling organelle.

    PubMed

    Tripathi, Durga Nand; Walker, Cheryl Lyn

    2016-04-01

    Peroxisomes participate in lipid metabolism, and are a major source of ROS in the cell. Their importance in cellular energy balance and redox homeostasis is well-established, as is the need to maintain peroxisome homeostasis to prevent pathologies associated with too few, or too many, of these organelles. How cells regulate peroxisome number has remained somewhat elusive. Recently, the tumor suppressors ATM and TSC, which regulate mTORC1 signaling, have been localized to peroxisomes. When activated by peroxisomal ROS, ATM signals to TSC to repress mTORC1 signaling and increase autophagic flux in cells, and also phosphorylates the peroxisomal protein PEX 5 to target peroxisomes for selective autophagy (pexophagy), providing a mechanism for regulation of peroxisomal homeostasis using ROS as a rheostat.

  2. The peroxisome as a cell signaling organelle.

    PubMed

    Tripathi, Durga Nand; Walker, Cheryl Lyn

    2016-04-01

    Peroxisomes participate in lipid metabolism, and are a major source of ROS in the cell. Their importance in cellular energy balance and redox homeostasis is well-established, as is the need to maintain peroxisome homeostasis to prevent pathologies associated with too few, or too many, of these organelles. How cells regulate peroxisome number has remained somewhat elusive. Recently, the tumor suppressors ATM and TSC, which regulate mTORC1 signaling, have been localized to peroxisomes. When activated by peroxisomal ROS, ATM signals to TSC to repress mTORC1 signaling and increase autophagic flux in cells, and also phosphorylates the peroxisomal protein PEX 5 to target peroxisomes for selective autophagy (pexophagy), providing a mechanism for regulation of peroxisomal homeostasis using ROS as a rheostat. PMID:26967755

  3. Prostaglandin synthesis inhibitors reduce Cannabis and restraint stress induced increase in rat brain serotonin concentrations.

    PubMed

    Bhattacharya, S K; Bhattacharya, D

    1983-01-01

    Cannabis resin (CI) produced a dose-related increase in rat brain serotonin concentrations, whereas restraint stress produced maximal rise of the neurotransmitter concentrations at 1 h, followed by a tendency to normalise by 4 h. The prostaglandin (PG) synthesis inhibitors, diclofenac and paracetamol, antagonized CI and restraint stress induced rise in serotonin concentrations. The findings lend credence to earlier reports that PG synthesis inhibitors antagonize serotonin-mediated neuropharmacological actions of CI and restraint stress in rats.

  4. Combined Treatment With Peroxisome Proliferator-Activated Receptor (PPAR) Gamma Ligands and Gamma Radiation Induces Apoptosis by PPARγ-Independent Up-Regulation of Reactive Oxygen Species-Induced Deoxyribonucleic Acid Damage Signals in Non-Small Cell Lung Cancer Cells

    SciTech Connect

    Han, Eun Jong; Im, Chang-Nim; Park, Seon Hwa; Moon, Eun-Yi; Hong, Sung Hee

    2013-04-01

    Purpose: To investigate possible radiosensitizing activities of the well-known peroxisome proliferator-activated receptor (PPAR)γ ligand ciglitazone and novel PPARγ ligands CAY10415 and CAY10506 in non-small cell lung cancer (NSCLC) cells. Methods and Materials: Radiosensitivity was assessed using a clonogenic cell survival assay. To investigate the mechanism underlying PPARγ ligand-induced radiosensitization, the subdiploid cellular DNA fraction was analyzed by flow cytometry. Activation of the caspase pathway by combined PPARγ ligands and γ-radiation treatment was detected by immunoblot analysis. Reactive oxygen species (ROS) were measured using 2,7-dichlorodihydrofluorescein diacetate and flow cytometry. Results: The 3 PPARγ ligands induced cell death and ROS generation in a PPARγ-independent manner, enhanced γ-radiation–induced apoptosis and caspase-3–mediated poly (ADP-ribose) polymerase (PARP) cleavage in vitro. The combined PPARγ ligand/γ-radiation treatment triggered caspase-8 activation, and this initiator caspase played an important role in the combination-induced apoptosis. Peroxisome proliferator-activated receptor-γ ligands may enhance the γ-radiation-induced DNA damage response, possibly by increasing γ-H2AX expression. Moreover, the combination treatment significantly increased ROS generation, and the ROS scavenger N-acetylcysteine inhibited the combined treatment-induced ROS generation and apoptotic cell death. Conclusions: Taken together, these results indicated that the combined treatment of PPARγ ligands and γ-radiation synergistically induced DNA damage and apoptosis, which was regulated by ROS.

  5. Apoptotic action of peroxisome proliferator-activated receptor-gamma activation in human non small-cell lung cancer is mediated via proline oxidase-induced reactive oxygen species formation.

    PubMed

    Kim, Ki Young; Ahn, Jin Hee; Cheon, Hyae Gyeong

    2007-09-01

    Peroxisome proliferator-activated receptor (PPAR)-gamma ligands have been shown to inhibit human lung cancers by inducing apoptosis and differentiation. In the present study, we elucidated the apoptotic mechanism of PPARgamma activation in human lung cancers by using a novel PPARgamma agonist, 1-(trans-methylimino-N-oxy)-6-(2-morpholinoethoxy)-3-phenyl-(1H-indene-2-carboxylic acid ethyl ester (KR-62980), and rosiglitazone. PPARgamma activation selectively inhibited cell viability of non-small-cell lung cancer with little effect on small-cell lung cancer and normal lung cells. The cell death induced by PPARgamma activation presented apoptotic features of oligonucleosomal DNA fragmentation in A549 human non-small-cell lung cancer cell line. Reactive oxygen species (ROS) production was accompanied by increased expression of proline oxidase (POX), a redox enzyme expressed in mitochondria, upon incubation with the agonists. POX RNA interference treatment blocked PPARgamma-induced ROS formation and cytotoxicity, suggesting that POX plays a functional role in apoptosis through ROS formation. The apoptotic effects by the agonists were antagonized by bisphenol A diglycidyl ether, a PPARgamma antagonist, and by knockdown of PPARgamma expression, indicating the involvement of PPARgamma in these actions. The results of the present study suggest that PPARgamma activation induces apoptotic cell death in non-small-cell lung carcinoma mainly through ROS formation via POX induction.

  6. Cancerous inhibitor of protein phosphatase 2A determines bortezomib-induced apoptosis in leukemia cells

    PubMed Central

    Liu, Chun-Yu; Shiau, Chung-Wai; Kuo, Hsin-Yu; Huang, Hsiang-Po; Chen, Ming-Huang; Tzeng, Cheng-Hwai; Chen, Kuen-Feng

    2013-01-01

    The multiple cellular targets affected by proteasome inhibition implicate a potential role for bortezomib, a first-in-class proteasome inhibitor, in enhancing antitumor activities in hematologic malignancies. Here, we examined the antitumor activity and drug targets of bortezomib in leukemia cells. Human leukemia cell lines were used for in vitro studies. Drug efficacy was evaluated by apoptosis assays and associated molecular events assessed by Western Blot. Gene silencing was performed by small interference RNA. Drug was tested in vivo in xenograft models of human leukemia cell lines and in primary leukemia cells. Clinical samples were assessed by immunohistochemical staining. Bortezomib differentially induced apoptosis in leukemia cells that was independent of its proteasome inhibition. Cancerous inhibitor of protein phosphatase 2A, a cellular inhibitor of protein phosphatase 2A, mediated the apoptotic effect of bortezomib. Bortezomib increased protein phosphatase 2A activity in sensitive leukemia cells (HL-60 and KG-1), but not in resistant cells (MOLT-3 and K562). Bortezomib’s downregulation of cancerous inhibitor of protein phosphatase 2A and phospho-Akt correlated with its drug sensitivity. Furthermore, cancerous inhibitor of protein phosphatase 2A negatively regulated protein phosphatase 2A activity. Ectopic expression of CIP2A up-regulated phospho-Akt and protected HL-60 cells from bortezomib-induced apoptosis, whereas silencing CIP2A overcame the resistance to bortezomib-induced apoptosis in MOLT3 and K562 cells. Importantly, bortezomib exerted in vivo antitumor activity in HL-60 xenografted tumors and induced cell death in some primary leukemic cells. Cancerous inhibitor of protein phosphatase 2A was expressed in leukemic blasts from bone marrow samples. Cancerous inhibitor of protein phosphatase 2A plays a major role in mediating bortezomib-induced apoptosis in leukemia cells. PMID:22983581

  7. Elevation of cortical C26:0 due to the decline of peroxisomal β-oxidation potentiates amyloid β generation and spatial memory deficits via oxidative stress in diabetic rats.

    PubMed

    Shi, Y; Sun, X; Sun, Y; Hou, L; Yao, M; Lian, K; Li, J; Lu, X; Jiang, L

    2016-02-19

    Diabetes mellitus correlates with subsequent development of Alzheimer's disease (AD). An accumulation of very long chain fatty acids (VLCFAs) was observed in AD brains. We found previously that inhibiting peroxisomal β-oxidation by an inhibitor caused increases in VLCFA and β-amyloid peptide (Aβ) in the cortex and primary cultured neurons of rats. Therefore, we investigated whether there was an impaired peroxisomal β-oxidation and elevated VLCFA related to the increased Aβ in the diabetic brain. This study was conducted in a type 2 diabetic rat model induced by a high-fat diet and low-dose streptozotocin. A decrease in peroxisomal β-oxidation activity caused by down-regulated thiolase expression and a consequent increase in C26:0 were observed. Meanwhile, decreases in eicosapentenoic acid (EPA) and increases in oxidative stress [indicated by levels of malondialdehyde (MDA), and the protein expression of NOX4, p47(phox) and HO-1], Aβ, and the expression of AβPP and BACE1, two proteins involved in Aβ production, were observed. C26:0 levels were positively correlated with Aβ and MDA. This work suggests that in addition to decreases in EPA, increases in C26:0 by impaired peroxisomal β-oxidation can be a potential risk factor contributing to the progression of AD in diabetic brains via inducing oxidative stress.

  8. Peroxisomes and sexual development in fungi

    PubMed Central

    Peraza-Reyes, Leonardo; Berteaux-Lecellier, Véronique

    2013-01-01

    Peroxisomes are versatile and dynamic organelles that are essential for the development of most eukaryotic organisms. In fungi, many developmental processes, such as sexual development, require the activity of peroxisomes. Sexual reproduction in fungi involves the formation of meiotic-derived sexual spores, often takes place inside multicellular fruiting bodies and requires precise coordination between the differentiation of multiple cell types and the progression of karyogamy and meiosis. Different peroxisomal functions contribute to the orchestration of this complex developmental process. Peroxisomes are required to sustain the formation of fruiting bodies and the maturation and germination of sexual spores. They facilitate the mobilization of reserve compounds via fatty acid β-oxidation and the glyoxylate cycle, allowing the generation of energy and biosynthetic precursors. Additionally, peroxisomes are implicated in the progression of meiotic development. During meiotic development in Podospora anserina, there is a precise modulation of peroxisome assembly and dynamics. This modulation includes changes in peroxisome size, number and localization, and involves a differential activity of the protein-machinery that drives the import of proteins into peroxisomes. Furthermore, karyogamy, entry into meiosis and sorting of meiotic-derived nuclei into sexual spores all require the activity of peroxisomes. These processes rely on different peroxisomal functions and likely depend on different pathways for peroxisome assembly. Indeed, emerging studies support the existence of distinct import channels for peroxisomal proteins that contribute to different developmental stages. PMID:24046747

  9. Fis1, DLP1, and Pex11p coordinately regulate peroxisome morphogenesis

    SciTech Connect

    Kobayashi, Shinta; Tanaka, Atsushi; Fujiki, Yukio . E-mail: yfujiscb@mbox.nc.kyushu-u.ac.jp

    2007-05-01

    Dynamin-like protein 1 (DLP1) and Pex11p{beta} function in morphogenesis of peroxisomes. In the present work, we investigated whether Fis1 is involved in fission of peroxisomes. Endogenous Fis1 was morphologically detected in peroxisomes as well as mitochondria in wild-type CHO-K1 and DLP1-defective ZP121 cells. Subcellular fractionation studies also revealed the presence of Fis1 in peroxisomes. Peroxisomal Fis1 showed the same topology, i.e., C-tail anchored membrane protein, as the mitochondrial one. Furthermore, ectopic expression of FIS1 induced peroxisome proliferation in CHO-K1 cells, while the interference of FIS1 RNA resulted in tubulation of peroxisomes, hence reducing the number of peroxisomes. Fis1 interacted with Pex11p{beta}, by direct binding apparently involving the C-terminal region of Pex11p{beta} in the interaction. Pex11p{beta} also interacted with each other, whereas the binding of Pex11p{beta} to DLP1 was not detectable. Moreover, ternary complexes comprising Fis1, Pex11p{beta}, and DLP1 were detected by chemical cross-linking. We also showed that the highly conserved N-terminal domain of Pex11p{beta} was required for the homo-oligomerization of Pex11p{beta} and indispensable for the peroxisome-proliferating activity. Taken together, these findings indicate that Fis1 plays important roles in peroxisome division and maintenance of peroxisome morphology in mammalian cells, possibly in a concerted manner with Pex11p{beta} and DLP1.

  10. Proton pump inhibitor-induced hypomagnesemia: A new challenge.

    PubMed

    Florentin, Matilda; Elisaf, Moses S

    2012-12-01

    Proton pump inhibitors (PPIs) are commonly used in clinical practice for the prevention and treatment of peptic ulcer, gastritis, esophagitis and gastroesophageal reflux. Hypomagnesemia has recently been recognized as a side effect of PPIs. Low magnesium levels may cause symptoms from several systems, some of which being potentially serious, such as tetany, seizures and arrhythmias. It seems that PPIs affect the gastrointestinal absorption of magnesium. Clinicians should be vigilant in order to timely consider and prevent or reverse hypomagnesemia in patients who take PPIs, especially if they are prone to this electrolyte disorder.

  11. Allosteric inhibitors of inducible nitric oxide synthase dimerization discovered via combinatorial chemistry

    PubMed Central

    McMillan, Kirk; Adler, Marc; Auld, Douglas S.; Baldwin, John J.; Blasko, Eric; Browne, Leslie J.; Chelsky, Daniel; Davey, David; Dolle, Ronald E.; Eagen, Keith A.; Erickson, Shawn; Feldman, Richard I.; Glaser, Charles B.; Mallari, Cornell; Morrissey, Michael M.; Ohlmeyer, Michael H. J.; Pan, Gonghua; Parkinson, John F.; Phillips, Gary B.; Polokoff, Mark A.; Sigal, Nolan H.; Vergona, Ronald; Whitlow, Marc; Young, Tish A.; Devlin, James J.

    2000-01-01

    Potent and selective inhibitors of inducible nitric oxide synthase (iNOS) (EC 1.14.13.39) were identified in an encoded combinatorial chemical library that blocked human iNOS dimerization, and thereby NO production. In a cell-based iNOS assay (A-172 astrocytoma cells) the inhibitors had low-nanomolar IC50 values and thus were >1,000-fold more potent than the substrate-based direct iNOS inhibitors 1400W and N-methyl-l-arginine. Biochemical studies confirmed that inhibitors caused accumulation of iNOS monomers in mouse macrophage RAW 264.7 cells. High affinity (Kd ≈ 3 nM) of inhibitors for isolated iNOS monomers was confirmed by using a radioligand binding assay. Inhibitors were >1,000-fold selective for iNOS versus endothelial NOS dimerization in a cell-based assay. The crystal structure of inhibitor bound to the monomeric iNOS oxygenase domain revealed inhibitor–heme coordination and substantial perturbation of the substrate binding site and the dimerization interface, indicating that this small molecule acts by allosterically disrupting protein–protein interactions at the dimer interface. These results provide a mechanism-based approach to highly selective iNOS inhibition. Inhibitors were active in vivo, with ED50 values of <2 mg/kg in a rat model of endotoxin-induced systemic iNOS induction. Thus, this class of dimerization inhibitors has broad therapeutic potential in iNOS-mediated pathologies. PMID:10677491

  12. PKC/MEK inhibitors suppress oxaliplatin-induced neuropathy and potentiate the antitumor effects.

    PubMed

    Tsubaki, Masanobu; Takeda, Tomoya; Tani, Tadahumi; Shimaoka, Hirotaka; Suzuyama, Naohiro; Sakamoto, Kotaro; Fujita, Arisa; Ogawa, Naoki; Itoh, Tatsuki; Imano, Motohiro; Funakami, Yoshinori; Ichida, Seiji; Satou, Takao; Nishida, Shozo

    2015-07-01

    Oxaliplatin is a key drug commonly used in colorectal cancer treatment. Despite high clinical efficacy, its therapeutic application is limited by common, dose-limiting occurrence of neuropathy. As usual symptomatic neuropathy treatments fail to improve the patients' condition, there is an urgent need to advance our understanding of the pathogenesis of neuropathy to propose effective therapy and ensure adequate pain management. Oxaliplatin-induced neuropathy was recently reported to be associated with protein kinase C (PKC) activation. It is unclear, however, whether PKC inhibition can prevent neuropathy. In our current studies, we found that a PKC inhibitor, tamoxifen, inhibited oxaliplatin-induced neuropathy via the PKC/extracellular signal-regulated kinase (ERK)/c-Fos pathway in lumbar spinal cords (lumbar segments 4-6). Additionally, tamoxifen was shown to act in synergy with oxaliplatin to inhibit growth in tumor cells-implanted mice. Moreover, mitogen-activated protein kinase kinase (MEK) 1/2 inhibitor, PD0325901, suppressed oxaliplatin-induced neuropathy and enhanced oxaliplatin efficacy. Our results indicate that oxaliplatin-induced neuropathy is associated with PKC/ERK/c-Fos pathway in lumbar spinal cord. Additionally, we demonstrate that disruption of this pathway by PKC and MEK inhibitors suppresses oxaliplatin-induced neuropathy, thereby suggesting that PKC and MEK inhibitors may be therapeutically useful in preventing oxaliplatin-induced neuropathy and could aid in combination antitumor pharmacotherapy.

  13. Proteasome inhibitors attenuated cholesterol-induced cardiac hypertrophy in H9c2 cells.

    PubMed

    Lee, Hyunjung; Park, Jinyoung; Kim, Eunice EunKyeong; Yoo, Young Sook; Song, Eun Joo

    2016-05-01

    The Ubiquitin proteasome system (UPS) plays roles in protein degradation, cell cycle control, and growth and inflammatory cell signaling. Dysfunction of UPS in cardiac diseases has been seen in many studies. Cholesterol acts as an inducer of cardiac hypertrophy. In this study, the effect of proteasome inhibitors on the cholesterol-induced hypertrophic growth in H9c2 cells is examined in order to observe whether UPS is involved in cardiac hypertrophy. The treatment of proteasome inhibitors MG132 and Bortezomib markedly reduced cellular surface area and mRNA expression of β-MHC in cholesterol-induced cardiac hypertrophy. In addition, activated AKT and ERK were significantly attenuated by MG132 and Bortezomib in cholesterol- induced cardiac hypertrophy. We demonstrated that cholesterol- induced cardiac hypertrophy was suppressed by proteasome inhibitors. Thus, regulatory mechanism of cholesterol- induced cardiac hypertrophy by proteasome inhibitors may provide a new therapeutic strategy to prevent the progression of heart failure. [BMB Reports 2016; 49(5): 270-275]. PMID:26592933

  14. Proteasome inhibitors attenuated cholesterol-induced cardiac hypertrophy in H9c2 cells

    PubMed Central

    Lee, Hyunjung; Park, Jinyoung; Kim, Eunice EunKyeong; Yoo, Young Sook; Song, Eun Joo

    2016-01-01

    The Ubiquitin proteasome system (UPS) plays roles in protein degradation, cell cycle control, and growth and inflammatory cell signaling. Dysfunction of UPS in cardiac diseases has been seen in many studies. Cholesterol acts as an inducer of cardiac hypertrophy. In this study, the effect of proteasome inhibitors on the cholesterol-induced hypertrophic growth in H9c2 cells is examined in order to observe whether UPS is involved in cardiac hypertrophy. The treatment of proteasome inhibitors MG132 and Bortezomib markedly reduced cellular surface area and mRNA expression of β-MHC in cholesterol-induced cardiac hypertrophy. In addition, activated AKT and ERK were significantly attenuated by MG132 and Bortezomib in cholesterol-induced cardiac hypertrophy. We demonstrated that cholesterol-induced cardiac hypertrophy was suppressed by proteasome inhibitors. Thus, regulatory mechanism of cholesterol-induced cardiac hypertrophy by proteasome inhibitors may provide a new therapeutic strategy to prevent the progression of heart failure. [BMB Reports 2016; 49(5): 270-275] PMID:26592933

  15. Microtubule inhibitors block the morphological changes induced in Drosophila blood cells by a parasitoid wasp factor.

    PubMed

    Rizki, R M; Rizki, T M

    1990-03-15

    The shape change of Drosophila melanogaster blood cells (lamellocytes) from discoidal to bipolar that is caused by a factor from the female parasitoid Leptopilina heterotoma is blocked by the tubulin inhibitors vinblastine and vincristine in vitro. The actin inhibitor, cytochalasin B, causes arborization of Drosophila lamellocytes and acts synergistically with the wasp factor to alter lamellocyte morphology. Lamellocyte aborization induced by cytochalasin B is blocked by simultaneous treatment with vinblastine. These observations indicate that the changes in lamellocyte shape induced by both the wasp factor and cytochalasin B require microtubule assembly. PMID:2311722

  16. Peroxisomes are platforms for cytomegalovirus’ evasion from the cellular immune response

    PubMed Central

    Magalhães, Ana Cristina; Ferreira, Ana Rita; Gomes, Sílvia; Vieira, Marta; Gouveia, Ana; Valença, Isabel; Islinger, Markus; Nascimento, Rute; Schrader, Michael; Kagan, Jonathan C.; Ribeiro, Daniela

    2016-01-01

    The human cytomegalovirus developed distinct evasion mechanisms from the cellular antiviral response involving vMIA, a virally-encoded protein that is not only able to prevent cellular apoptosis but also to inhibit signalling downstream from mitochondrial MAVS. vMIA has been shown to localize at mitochondria and to trigger their fragmentation, a phenomenon proven to be essential for the signalling inhibition. Here, we demonstrate that vMIA is also localized at peroxisomes, induces their fragmentation and inhibits the peroxisomal-dependent antiviral signalling pathway. Importantly, we demonstrate that peroxisomal fragmentation is not essential for vMIA to specifically inhibit signalling downstream the peroxisomal MAVS. We also show that vMIA interacts with the cytoplasmic chaperone Pex19, suggesting that the virus has developed a strategy to highjack the peroxisomal membrane proteins’ transport machinery. Furthermore, we show that vMIA is able to specifically interact with the peroxisomal MAVS. Our results demonstrate that peroxisomes constitute a platform for evasion of the cellular antiviral response and that the human cytomegalovirus has developed a mechanism by which it is able to specifically evade the peroxisomal MAVS-dependent antiviral signalling. PMID:27181750

  17. Effects of octadecanoid metabolites and inhibitors on induced nicotine accumulation inNicotiana sylvestris.

    PubMed

    Baldwin, I T; Schmelz, E A; Zhang, Z P

    1996-01-01

    We examined the effects of inhibitors of the octadecanoid pathway (n-propyl gallate, acetosalicylic acid, salicylhydroxamic acid, methyl salicylate, and antipyrine) on wound- and jasmonate-induced nicotine accumulation and compared the nicotine-inducing ability of exogeneous additions of linolenic acid (18:3) and its methyl ester, linoleic acid (18:2), abscisic acid, traumatic acid, and methyl dihydrojasmonate to the nicotine-inducing ability of exogenous additions of methyl jasmonate (MJ). The first four of these inhibitors significantly reduced wound-induced nicotine accumulation when applied in a lanolin paste to wounded tissues immediately after wounding at concentrations of 89-90µg/plant. When methyl salicylate and propyl gallate were mixed individually with MJ, neither inhibited MJ-induced nicotine synthesis, which suggests that the inhibitors block jasmonate synthesis or release from stored pools and not its effects. Linolenic acid or its methyl ester applied to undamaged plants or damaged plants (to either damaged or undamaged leaves) or to the roots of hydroponically growing plants did not induce nicotine accumulation or increase nicotine accumulation above levels found in damaged plants. Similarly, traumatic acid, linoleic acid, and abscisic acid did not induce nicotine accumulations. Methyl dihydrojasmonate, which is biosynthetically derived from linoleic acid, had 12-56% of the nicotine-inducing acitivity of MJ when added to the roots of hydroponically grown plants. The signal transduction pathway mediating wound-induced nicotine production therefore shares many features of the pathway eliciting wound-induced proteinase inhibitor production but differs in not being regulated at the lipase step in jasmonic acid production and not being responsive to abscisic acid. PMID:24226983

  18. Location of inhibitor binding sites in the human inducible prostaglandin E synthase, MPGES1.

    PubMed

    Prage, Edward B; Pawelzik, Sven-Christian; Busenlehner, Laura S; Kim, Kwangho; Morgenstern, Ralf; Jakobsson, Per-Johan; Armstrong, Richard N

    2011-09-01

    The inducible microsomal prostaglandin E(2) synthase 1 (MPGES1) is an integral membrane protein coexpressed with and functionally coupled to cyclooxygenase 2 (COX-2) generating the pro-inflammatory molecule PGE(2). The development of effective inhibitors of MPGES1 holds promise as a highly selective route for controlling inflammation. In this paper, we describe the use of backbone amide H/D exchange mass spectrometry to map the binding sites of different types of inhibitors of MPGES1. The results reveal the locations of specific inhibitor binding sites that include the GSH binding site and a hydrophobic cleft in the protein thought to accommodate the prostaglandin H(2) substrate. In the absence of three-dimensional crystal structures of the enzyme-bound inhibitors, the results provide clear physical evidence that three pharmacologically active inhibitors bind in a hydrophobic cleft composed of sections of transmembrane helices Ia, IIb, IIIb, and IVb at the interface of subunits in the trimer. In principle, the H/D exchange behavior of the protein can be used as a preliminary guide for optimization of inhibitor efficacy. Finally, a comparison of the structures and H/D exchange behavior of MPGES1 and the related enzyme MGST1 in the presence of glutathione and the inhibitor glutathione sulfonate confirms the unusual observation that two proteins from the same superfamily harbor GSH binding sites in different locations.

  19. nNOS inhibitors attenuate methamphetamine-induced dopaminergic neurotoxicity but not hyperthermia in mice.

    PubMed

    Itzhak, Y; Martin, J L; Ail, S F

    2000-09-11

    Methamphetamine (METH)-induced dopaminergic neurotoxicity is associated with hyperthermia. We investigated the effect of several neuronal nitric oxide synthase (nNOS) inhibitors on METH-induced hyperthermia and striatal dopaminergic neurotoxicity. Administration of METH (5 mg/kg; q. 3 h x 3) to Swiss Webster mice produced marked hyperthermia and 50-60% depletion of striatal dopaminergic markers 72 h after METH administration. Pretreatment with the nNOS inhibitors S-methylthiocitrulline (SMTC; 10 mg/kg) or 3-bromo-7-nitroindazole (3-Br-7-NI; 20 mg/kg) before each METH injection did not affect the persistent hyperthermia produced by METH, but afforded protection against the depletion of dopaminergic markers. A low dose (25 mg/kg) of the nNOS inhibitor 7-nitroindazole (7-NI) did not affect METH-induced hyperthermia, but a high dose (50 mg/kg) produced significant hypothermia. These findings indicate that low dose of selective nNOS inhibitors protect against METH-induced neurotoxicity with no effect on body temperature and support the hypothesis that nitric oxide (NO) and peroxynitrite have a major role in METH-induced dopaminergic neurotoxicity.

  20. Activating PTEN by COX-2 inhibitors antagonizes radiation-induced AKT activation contributing to radiosensitization.

    PubMed

    Meng, Zhen; Gan, Ye-Hua

    2015-05-01

    Radiotherapy is still one of the most effective nonsurgical treatments for many tumors. However, radioresistance remains a major impediment to radiotherapy. Although COX-2 inhibitors can induce radiosensitization, the underlying mechanism is not fully understood. In this study, we showed that COX-2 selective inhibitor celecoxib enhanced the radiation-induced inhibition of cell proliferation and apoptosis in HeLa and SACC-83 cells. Treatment with celecoxib alone dephosphorylated phosphatase and tensin homolog deleted on chromosome ten (PTEN), promoted PTEN membrane translocation or activation, and correspondingly dephosphorylated or inactivated protein kinase B (AKT). By contrast, treatment with radiation alone increased PTEN phosphorylation, inhibited PTEN membrane translocation and correspondingly activated AKT in the two cell lines. However, treatment with celecoxib or another COX-2 selective inhibitor (valdecoxib) completely blocked radiation-induced increase of PTEN phosphorylation, rescued radiation-induced decrease in PTEN membrane translocation, and correspondingly inactivated AKT. Moreover, celecoxib could also upregulate PTEN protein expression by downregulating Sp1 expression, thereby leading to the activation of PTEN transcription. Our results suggested that COX-2 inhibitors could enhance radiosensitization at least partially by activating PTEN to antagonize radiation-induced AKT activation.

  1. ARP101, a selective MMP-2 inhibitor, induces autophagy-associated cell death in cancer cells.

    PubMed

    Jo, Yoon Kyung; Park, So Jung; Shin, Ji Hyun; Kim, Yunha; Hwang, Jung Jin; Cho, Dong-Hyung; Kim, Jin Cheon

    2011-01-28

    Autophagy is a catabolic cellular process involving self-digestion and turnover of macromolecules and entire organelles. Autophagy is primarily a protective process in response to cellular stress, but it can be associated with cell death. Genetic evidence also supports autophagy function as a tumor suppressor mechanism. To identify specific regulators to autophagy, we screened the Lopac 1280 and the Prestwick chemical libraries using a cell-based screening system with autophagy marker (green fluorescence protein conjugated LC3 protein (GFP-LC3)). We identified ARP101, a selective matrix metalloproteinase-2 (MMP-2) inhibitor as one of the most potent inducer of autophagy. ARP101 treatment was highly effective in inducing the formation of autophagosome and conversion of LC3I into LC3II. Moreover, ARP101-induced autophagy was completely blocked in mouse embryo fibroblasts that lacked autophagy related gene 5 (ATG5(-/-) MEF). Interestingly, cell death induced by ARP101 was not inhibited by zVAD, a pan caspase inhibitor, whereas, it was efficiently suppressed by addition of 3-methyladenine, an autophagy inhibitor. These results suggest that the selective MMP-2 inhibitor, ARP101, induces autophagy and autophagy-associated cell death. PMID:21187062

  2. Inhibitors that stabilize a closed RAF kinase domain conformation induce dimerization

    PubMed Central

    Lavoie, Hugo; Thevakumaran, Neroshan; Gavory, Gwenaëlle; Li, John; Padeganeh, Abbas; Guiral, Sébastien; Duchaine, Jean; Mao, Daniel Y. L.; Bouvier, Michel; Sicheri, Frank; Therrien, Marc

    2016-01-01

    RAF kinases play a prominent role in cancer. Their mode of activation is complex, but critically requires dimerization of their kinase domains. Unexpectedly, several ATP-competitive RAF inhibitors were recently found to promote dimerization and transactivation of RAF kinases in a RAS-dependent manner and as a result undesirably stimulate RAS/ERK-mediated cell growth. The mechanism by which these inhibitors induce RAF kinase domain dimerization remains unclear. Here we describe BRET-based biosensors for the extended RAF family enabling the detection of RAF dimerization in living cells. Notably, we demonstrate the utility of these tools for profiling kinase inhibitors that selectively modulate RAF dimerization as well as for probing structural determinants of RAF dimerization in vivo. Our findings, which appear generalizable to other kinase families allosterically regulated by kinase domain dimerization, suggest a model whereby ATP-competitive inhibitors mediate RAF dimerization by stabilizing a rigid closed conformation of the kinase domain. PMID:23685672

  3. A novel mechanism by which small molecule inhibitors induce the DFG flip in Aurora A

    PubMed Central

    Martin, Mathew P.; Zhu, Jin-Yi; Lawrence, Harshani R.; Pireddu, Roberta; Luo, Yunting; Alam, Riazul; Ozcan, Sevil; Sebti, Said M.; Lawrence, Nicholas J.; Schönbrunn, Ernst

    2015-01-01

    Most protein kinases share a DFG (Asp-Phe-Gly) motif in the ATP site which can assume two distinct conformations, the active DFG-in and the inactive DFG-out states. Small molecule inhibitors able to induce the DFG-out state have received considerable attention in kinase drug discovery. Using a typical DFG-in inhibitor scaffold of Aurora A, a kinase involved in the regulation of cell division, we found that halogen and nitrile substituents directed at the N-terminally flanking residue Ala273 induced global conformational changes in the enzyme, leading to DFG-out inhibitors that are among the most potent Aurora A inhibitors reported to date. The data suggest an unprecedented mechanism of action, in which induced-dipole forces along the Ala273 side chain alter the charge distribution of the DFG backbone, allowing the DFG to unwind. As the ADFG sequence and three-dimensional structure is highly conserved, DFG-out inhibitors of other kinases may be designed by specifically targeting the flanking alanine residue with electric dipoles. PMID:22248356

  4. Peroxisomes in brain development and function.

    PubMed

    Berger, Johannes; Dorninger, Fabian; Forss-Petter, Sonja; Kunze, Markus

    2016-05-01

    Peroxisomes contain numerous enzymatic activities that are important for mammalian physiology. Patients lacking either all peroxisomal functions or a single enzyme or transporter function typically develop severe neurological deficits, which originate from aberrant development of the brain, demyelination and loss of axonal integrity, neuroinflammation or other neurodegenerative processes. Whilst correlating peroxisomal properties with a compilation of pathologies observed in human patients and mouse models lacking all or individual peroxisomal functions, we discuss the importance of peroxisomal metabolites and tissue- and cell type-specific contributions to the observed brain pathologies. This enables us to deconstruct the local and systemic contribution of individual metabolic pathways to specific brain functions. We also review the recently discovered variability of pathological symptoms in cases with unexpectedly mild presentation of peroxisome biogenesis disorders. Finally, we explore the emerging evidence linking peroxisomes to more common neurological disorders such as Alzheimer's disease, autism and amyotrophic lateral sclerosis. PMID:26686055

  5. Localization of peroxisomal matrix proteins by photobleaching

    SciTech Connect

    Buch, Charlotta; Hunt, Mary C.; Alexson, Stefan E.H.; Hallberg, Einar

    2009-10-16

    The distribution of some enzymes between peroxisomes and cytosol, or a dual localization in both these compartments, can be difficult to reconcile. We have used photobleaching in live cells expressing green fluorescent protein (GFP)-fusion proteins to show that imported bona fide peroxisomal matrix proteins are retained in the peroxisome. The high mobility of the GFP-fusion proteins in the cytosol and absence of peroxisomal escape makes it possible to eliminate the cytosolic fluorescence by photobleaching, to distinguish between exclusively cytosolic proteins and proteins that are also present at low levels in peroxisomes. Using this technique we found that GFP tagged bile acid-CoA:amino acid N-acyltransferase (BAAT) was exclusively localized in the cytosol in HeLa cells. We conclude that the cytosolic localization was due to its carboxyterminal non-consensus peroxisomal targeting signal (-SQL) since mutation of the -SQL to -SKL resulted in BAAT being efficiently imported into peroxisomes.

  6. Peroxisomes in brain development and function.

    PubMed

    Berger, Johannes; Dorninger, Fabian; Forss-Petter, Sonja; Kunze, Markus

    2016-05-01

    Peroxisomes contain numerous enzymatic activities that are important for mammalian physiology. Patients lacking either all peroxisomal functions or a single enzyme or transporter function typically develop severe neurological deficits, which originate from aberrant development of the brain, demyelination and loss of axonal integrity, neuroinflammation or other neurodegenerative processes. Whilst correlating peroxisomal properties with a compilation of pathologies observed in human patients and mouse models lacking all or individual peroxisomal functions, we discuss the importance of peroxisomal metabolites and tissue- and cell type-specific contributions to the observed brain pathologies. This enables us to deconstruct the local and systemic contribution of individual metabolic pathways to specific brain functions. We also review the recently discovered variability of pathological symptoms in cases with unexpectedly mild presentation of peroxisome biogenesis disorders. Finally, we explore the emerging evidence linking peroxisomes to more common neurological disorders such as Alzheimer's disease, autism and amyotrophic lateral sclerosis.

  7. Localization of peroxisomal matrix proteins by photobleaching.

    PubMed

    Buch, Charlotta; Hunt, Mary C; Alexson, Stefan E H; Hallberg, Einar

    2009-10-16

    The distribution of some enzymes between peroxisomes and cytosol, or a dual localization in both these compartments, can be difficult to reconcile. We have used photobleaching in live cells expressing green fluorescent protein (GFP)-fusion proteins to show that imported bona fide peroxisomal matrix proteins are retained in the peroxisome. The high mobility of the GFP-fusion proteins in the cytosol and absence of peroxisomal escape makes it possible to eliminate the cytosolic fluorescence by photobleaching, to distinguish between exclusively cytosolic proteins and proteins that are also present at low levels in peroxisomes. Using this technique we found that GFP tagged bile acid-CoA:amino acid N-acyltransferase (BAAT) was exclusively localized in the cytosol in HeLa cells. We conclude that the cytosolic localization was due to its carboxyterminal non-consensus peroxisomal targeting signal (-SQL) since mutation of the -SQL to -SKL resulted in BAAT being efficiently imported into peroxisomes.

  8. Shikonin, dually functions as a proteasome inhibitor and a necroptosis inducer in multiple myeloma cells.

    PubMed

    Wada, Naoko; Kawano, Yawara; Fujiwara, Shiho; Kikukawa, Yoshitaka; Okuno, Yutaka; Tasaki, Masayoshi; Ueda, Mitsuharu; Ando, Yukio; Yoshinaga, Kazuya; Ri, Masaki; Iida, Shinsuke; Nakashima, Takayuki; Shiotsu, Yukimasa; Mitsuya, Hiroaki; Hata, Hiroyuki

    2015-03-01

    Shikonin (SHK), a natural small agent (MW 288.3), reportedly induces cell death in various tumor cells. We have found that SHK also exerts potent cytocidal effects on human multiple myeloma (MM) cells, but its anticancer mechanism in MM cells remains to be elucidated. SHK at 2.5-5 µM induced apoptosis in seven MM cell lines, including the bortezomib-resistant cell line KMS11/BTZ. The IC50 value of SHK against KMS11/BTZ was comparable to that of a parental cell line KMS11 (1.1 and 1.56 µM, respectively). SHK induces accumulation of ubiquitinated proteins and activates XBP-1 in MM cells, suggesting that SHK functions as a proteasome inhibitor, eventually inducing ER stress-associated apoptosis. SHK increases levels of HSP70/72, which protects cells from apoptosis, and exerts greater cytocidal effects in combination with the HSP70/72 inhibitor VER-155008. At higher concentrations (10-20 µM), SHK induced cell death, which was completely inhibited by a necroptosis inhibitor, necrostatin-1 (Nec-1), while the cytocidal activity was unaffected by Z-VAD-FMK, strongly suggesting that cell death is induced by SHK at high concentrations through necroptosis. The present data show for the first time that SHK induces cell death in MM cells. SHK efficiently induces apoptosis and combination of heat shock protein inhibitor with low dose SHK enhances apoptosis, while high dose SHK induces necroptosis in MM cells. These findings together support the use of SHK as a potential therapeutic agent for MM. PMID:25530098

  9. Oxaliplatin Neurotoxicity Involves Peroxisome Alterations. PPARγ Agonism as Preventive Pharmacological Approach

    PubMed Central

    Zanardelli, Matteo; Micheli, Laura; Cinci, Lorenzo; Failli, Paola; Ghelardini, Carla; Di Cesare Mannelli, Lorenzo

    2014-01-01

    The development of neuropathic syndromes is an important, dose limiting side effect of anticancer agents like platinum derivates, taxanes and vinca alkaloids. The causes of neurotoxicity are still unclear but the impairment of the oxidative equilibrium is strictly related to pain. Two intracellular organelles, mitochondria and peroxisomes cooperate to the maintaining of the redox cellular state. Whereas a relationship between chemotherapy-dependent mitochondrial alteration and neuropathy has been established, the role of peroxisome is poor explored. In order to study the mechanisms of oxaliplatin-induced neurotoxicity, peroxisomal involvement was evaluated in vitro and in vivo. In primary rat astrocyte cell culture, oxaliplatin (10 µM for 48 h or 1 µM for 5 days) increased the number of peroxisomes, nevertheless expression and functionality of catalase, the most important antioxidant defense enzyme in mammalian peroxisomes, were significantly reduced. Five day incubation with the selective Peroxisome Proliferator Activated Receptor-γ (PPAR-γ) antagonist G3335 (30 µM) induced a similar peroxisomal impairment suggesting a relationship between PPARγ signaling and oxaliplatin neurotoxicity. The PPARγ agonist rosiglitazone (10 µM) reduced the harmful effects induced both by G3335 and oxaliplatin. In vivo, in a rat model of oxaliplatin induced neuropathy, a repeated treatment with rosiglitazone (3 and 10 mg kg−1 per os) significantly reduced neuropathic pain evoked by noxious (Paw pressure test) and non-noxious (Cold plate test) stimuli. The behavioral effect paralleled with the prevention of catalase impairment induced by oxaliplatin in dorsal root ganglia. In the spinal cord, catalase protection was showed by the lower rosiglitazone dosage without effect on the astrocyte density increase induced by oxaliplatin. Rosiglitazone did not alter the oxaliplatin-induced mortality of the human colon cancer cell line HT-29. These results highlight the role of

  10. Angiotensin type 2-receptor (AT2R) activation induces hypotension in apolipoprotein E-deficient mice by activating peroxisome proliferator-activated receptor-γ.

    PubMed

    Li, Ming; Tejada, Thor; Lambert, Jonathan P; Nicholson, Chad K; Yahiro, Eiji; Ambai, Vats T; Ali, Syeda F; Bradley, Eddie W; Graham, Robert M; Dell'Italia, Louis J; Calvert, John W; Naqvi, Nawazish

    2016-01-01

    Angiotensin II (Ang II) modulates blood pressure and atherosclerosis development through its vascular type-1 (AT1R) and type-2 (AT2R) receptors, which have opposing effects. AT2R activation produces hypotension, and is anti-atherogenic. Targeted overexpression of AT2Rs in vascular smooth muscle cells (VSMCs) indicates that these effects are due to increased nitric oxide (NO) generation. However, the role of endogenous VSMC AT2Rs in these events is unknown. Effect of 7-day low-dose Ang II-infusion (12 µg/kg/hr) on blood pressure was tested in 9-week-old apoE((-/-)) mice fed a low or high cholesterol diet (LCD or HCD, respectively). Cardiac output was measured by echocardiography. Immunohistochemistry was performed to localize and quantify AT2Rs and p-Ser(1177)-endothelial nitric oxide synthase (eNOS) levels in the aortic arch. PD123319 and GW-9662 were used to selectively block the AT2R and peroxisome proliferator-activated receptor-γ (PPAR-γ), respectively. Ang II infusion decreased blood pressure by 12 mmHg (P < 0.001) in LCD/apoE((-/-)) mice without altering cardiac output; a response blocked by PD123319. Although, AT2R stimulation neither activated eNOS (p-Ser(1177)-eNOS) nor changed plasma NO metabolites, it caused an ~6-fold increase in VSMC PPAR-γ levels (P < 0.001) and the AT2R-mediated hypotension was abolished by GW-9662. AT2R-mediated hypotension was also inhibited by HCD, which selectively decreased VSMC AT2R expression by ~6-fold (P < 0.01). These findings suggest a novel pathway for the Ang II/AT2R-mediated hypotensive response that involves PPAR-γ, and is down regulated by a HCD. PMID:27679746

  11. Angiotensin type 2-receptor (AT2R) activation induces hypotension in apolipoprotein E-deficient mice by activating peroxisome proliferator-activated receptor-γ

    PubMed Central

    Li, Ming; Tejada, Thor; Lambert, Jonathan P; Nicholson, Chad K; Yahiro, Eiji; Ambai, Vats T; Ali, Syeda F; Bradley, Eddie W; Graham, Robert M; Dell’Italia, Louis J; Calvert, John W; Naqvi, Nawazish

    2016-01-01

    Angiotensin II (Ang II) modulates blood pressure and atherosclerosis development through its vascular type-1 (AT1R) and type-2 (AT2R) receptors, which have opposing effects. AT2R activation produces hypotension, and is anti-atherogenic. Targeted overexpression of AT2Rs in vascular smooth muscle cells (VSMCs) indicates that these effects are due to increased nitric oxide (NO) generation. However, the role of endogenous VSMC AT2Rs in these events is unknown. Effect of 7-day low-dose Ang II-infusion (12 µg/kg/hr) on blood pressure was tested in 9-week-old apoE(-/-) mice fed a low or high cholesterol diet (LCD or HCD, respectively). Cardiac output was measured by echocardiography. Immunohistochemistry was performed to localize and quantify AT2Rs and p-Ser1177-endothelial nitric oxide synthase (eNOS) levels in the aortic arch. PD123319 and GW-9662 were used to selectively block the AT2R and peroxisome proliferator-activated receptor-γ (PPAR-γ), respectively. Ang II infusion decreased blood pressure by 12 mmHg (P < 0.001) in LCD/apoE(-/-) mice without altering cardiac output; a response blocked by PD123319. Although, AT2R stimulation neither activated eNOS (p-Ser1177-eNOS) nor changed plasma NO metabolites, it caused an ~6-fold increase in VSMC PPAR-γ levels (P < 0.001) and the AT2R-mediated hypotension was abolished by GW-9662. AT2R-mediated hypotension was also inhibited by HCD, which selectively decreased VSMC AT2R expression by ~6-fold (P < 0.01). These findings suggest a novel pathway for the Ang II/AT2R-mediated hypotensive response that involves PPAR-γ, and is down regulated by a HCD. PMID:27679746

  12. Angiotensin type 2-receptor (AT2R) activation induces hypotension in apolipoprotein E-deficient mice by activating peroxisome proliferator-activated receptor-γ

    PubMed Central

    Li, Ming; Tejada, Thor; Lambert, Jonathan P; Nicholson, Chad K; Yahiro, Eiji; Ambai, Vats T; Ali, Syeda F; Bradley, Eddie W; Graham, Robert M; Dell’Italia, Louis J; Calvert, John W; Naqvi, Nawazish

    2016-01-01

    Angiotensin II (Ang II) modulates blood pressure and atherosclerosis development through its vascular type-1 (AT1R) and type-2 (AT2R) receptors, which have opposing effects. AT2R activation produces hypotension, and is anti-atherogenic. Targeted overexpression of AT2Rs in vascular smooth muscle cells (VSMCs) indicates that these effects are due to increased nitric oxide (NO) generation. However, the role of endogenous VSMC AT2Rs in these events is unknown. Effect of 7-day low-dose Ang II-infusion (12 µg/kg/hr) on blood pressure was tested in 9-week-old apoE(-/-) mice fed a low or high cholesterol diet (LCD or HCD, respectively). Cardiac output was measured by echocardiography. Immunohistochemistry was performed to localize and quantify AT2Rs and p-Ser1177-endothelial nitric oxide synthase (eNOS) levels in the aortic arch. PD123319 and GW-9662 were used to selectively block the AT2R and peroxisome proliferator-activated receptor-γ (PPAR-γ), respectively. Ang II infusion decreased blood pressure by 12 mmHg (P < 0.001) in LCD/apoE(-/-) mice without altering cardiac output; a response blocked by PD123319. Although, AT2R stimulation neither activated eNOS (p-Ser1177-eNOS) nor changed plasma NO metabolites, it caused an ~6-fold increase in VSMC PPAR-γ levels (P < 0.001) and the AT2R-mediated hypotension was abolished by GW-9662. AT2R-mediated hypotension was also inhibited by HCD, which selectively decreased VSMC AT2R expression by ~6-fold (P < 0.01). These findings suggest a novel pathway for the Ang II/AT2R-mediated hypotensive response that involves PPAR-γ, and is down regulated by a HCD.

  13. BET and HDAC inhibitors induce similar genes and biological effects and synergize to kill in Myc-induced murine lymphoma

    PubMed Central

    Bhadury, Joydeep; Nilsson, Lisa M.; Veppil Muralidharan, Somsundar; Green, Lydia C.; Li, Zhoulei; Gesner, Emily M.; Hansen, Henrik C.; Keller, Ulrich B.; McLure, Kevin G.; Nilsson, Jonas A.

    2014-01-01

    The bromodomain and extraterminal (BET) domain family of proteins binds to acetylated lysines on histones and regulates gene transcription. Recently, BET inhibitors (BETi) have been developed that show promise as potent anticancer drugs against various solid and hematological malignancies. Here we show that the structurally novel and orally bioavailable BET inhibitor RVX2135 inhibits proliferation and induces apoptosis of lymphoma cells arising in Myc-transgenic mice in vitro and in vivo. We find that BET inhibition exhibits broad transcriptional effects in Myc-transgenic lymphoma cells affecting many transcription factor networks. By examining the genes induced by BETi, which have largely been ignored to date, we discovered that these were similar to those induced by histone deacetylase inhibitors (HDACi). HDACi also induced cell-cycle arrest and cell death of Myc-induced murine lymphoma cells and synergized with BETi. Our data suggest that BETi sensitize Myc-overexpressing lymphoma cells partly by inducing HDAC-silenced genes, and suggest synergistic and therapeutic combinations by targeting the genetic link between BETi and HDACi. PMID:24979794

  14. MAP KINASE ERK 1/2 INHIBITORS INDUCE DYSMORPHOLOGY IN MOUSE WHOLE EMBRYO CULTURE

    EPA Science Inventory

    ROSEN, M.B. and E. S. HUNTER. Reproductive Toxicology Division, NHEERL, ORD, U.S. EPA, Research Triangle Park, North Carolina. MAP kinase Erk1/2 inhibitors induce dysmorphology in mouse whole embryo culture.

    MAP Kinase signal transduction is associated with a variety ...

  15. Insect and wound induced GUS gene expression from a Beta vulgaris proteinase inhibitor gene promoter

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Inducible gene promoters that are specifically activated by pathogen invasion or insect pest attack are needed for effective expression of resistance genes to control plant diseases. In the present study, a promoter from a serine proteinase inhibitor gene (BvSTI) shown to be up-regulated in resist...

  16. Proteasome inhibitors induce apoptosis and reduce viral replication in primary effusion lymphoma cells

    SciTech Connect

    Saji, Chiaki; Higashi, Chizuka; Niinaka, Yasufumi; Yamada, Koji; Noguchi, Kohji; Fujimuro, Masahiro

    2011-12-02

    Highlights: Black-Right-Pointing-Pointer Constitutive NF-{kappa}B signaling is essential for the survival and growth of PEL cells. Black-Right-Pointing-Pointer NF-{kappa}B signaling is upregulated by the proteasome-dependent degradation of I{kappa}B{alpha}. Black-Right-Pointing-Pointer Proteasome inhibitors suppress NF-{kappa}B signaling and induce apoptosis in PEL cells through stabilization of I{kappa}B{alpha}. Black-Right-Pointing-Pointer Proteasome inhibitors suppress viral replication in PEL cells during lytic KSHV infection. -- Abstract: Primary effusion lymphoma (PEL) is an aggressive neoplasm caused by Kaposi's sarcoma-associated herpesvirus (KSHV). This study provides evidence that proteasomal activity is required for both survival of PEL cells stably harboring the KSHV genome and viral replication of KSHV. We evaluated the cytotoxic effects of proteasome inhibitors on PEL cells. The proteasome inhibitors MG132, lactacystin, and proteasome inhibitor I dramatically inhibited cell proliferation and induced apoptosis of PEL cells through the accumulation of p21 and p27. Furthermore, proteasome inhibitors induced the stabilization of NF-{kappa}B inhibitory molecule (I{kappa}B{alpha}) and suppressed the transcriptional activity of NF-{kappa}B in PEL cells. The NF-{kappa}B specific inhibitor BAY11-7082 also induced apoptosis in PEL cells. The constitutive activation of NF-{kappa}B signaling is essential for the survival and growth of B cell lymphoma cells, including PEL cells. NF-{kappa}B signaling is upregulated by proteasome-dependent degradation of I{kappa}B{alpha}. The suppression of NF-{kappa}B signaling by proteasome inhibitors may contribute to the induction of apoptosis in PEL cells. In addition, proteasome activity is required for KSHV replication in KSHV latently infected PEL cells. MG132 reduced the production of progeny virus from PEL cells at low concentrations, which do not affect PEL cell growth. These findings suggest that proteasome inhibitors

  17. Partial purification and properties of an exonuclease inhibitor induced by bacteriophage Mu-1.

    PubMed Central

    Williams, J G; Radding, C M

    1981-01-01

    From an induced lysogen of bacteriophage Mu-1, we partially purified a substance of high molecular weight that blocks the action of several exonucleases on double-stranded DNA. The presence of the inhibitor in cell-free extracts is dependent on induction of a Mu prophage. The Mu-related inhibitor acts by binding to double-stranded DNA rather than by interacting with the DNase. The inhibitor protects linear duplex DNA of Mu, P22, and phi X174am3 from exonucleolytic degradation by recBC DNase and lambda exonuclease. Single-stranded DNA, however, is not protected by the inhibitor from degradation by either recBC DNase or exonuclease I. The inhibitor preparation contains a protein that binds to linear duplex DNA, but not to circular duplex DNA; ends are required for binding to occur. Single-stranded DNA is not a substrate for the binding protein. These and other results suggest that the binding protein and the inhibitor are the same activity. Images PMID:6268842

  18. The EMT-activator ZEB1 induces bone metastasis associated genes including BMP-inhibitors

    PubMed Central

    Mock, Kerstin; Preca, Bogdan-Tiberius; Brummer, Tilman; Brabletz, Simone; Stemmler, Marc P.; Brabletz, Thomas

    2015-01-01

    Tumor cell invasion, dissemination and metastasis is triggered by an aberrant activation of epithelial-to-mesenchymal transition (EMT), often mediated by the transcription factor ZEB1. Disseminating tumor cells must acquire specific features that allow them to colonize at different organ sites. Here we identify a set of genes that is highly expressed in breast cancer bone metastasis and activated by ZEB1. This gene set includes various secreted factors, e.g. the BMP-inhibitor FST, that are described to reorganize the bone microenvironment. By inactivating BMP-signaling, BMP-inhibitors are well-known to induce osteolysis in development and disease. We here demonstrate that the expression of ZEB1 and BMP-inhibitors is correlated with bone metastasis, but not with brain or lung metastasis of breast cancer patients. In addition, we show that this correlated expression pattern is causally linked, as ZEB1 induces the expression of the BMP-inhibitors NOG, FST and CHRDL1 both by directly increasing their gene transcription, as well as by indirectly suppressing their reduction via miR-200 family members. Consequently, ZEB1 stimulates BMP-inhibitor mediated osteoclast differentiation. These findings suggest that ZEB1 is not only driving EMT, but also contributes to the formation of osteolytic bone metastases in breast cancer. PMID:25973542

  19. Transcriptional induction of GRP78/BiP by histone deacetylase inhibitors and resistance to histone deacetylase inhibitor-induced apoptosis

    PubMed Central

    Baumeister, Peter; Dong, Dezheng; Fu, Yong; Lee, Amy S.

    2009-01-01

    Histone deacetylase (HDAC) inhibitors are emerging as effective therapies in the treatment of cancer, and the role of HDACs in the regulation of promoters is rapidly expanding. GRP78/BiP is a stress inducible endoplasmic reticulum (ER) chaperone with anti-apoptotic properties. We present here the mechanism for repression of the Grp78 promoter by histone deacetylase 1 (HDAC1). Our studies reveal that HDAC inhibitors specifically induce GRP78, and the induction level is amplified by ER stress. Through mutational analysis, we have identified the minimal Grp78 promoter and specific elements responsible for HDAC-mediated repression. We show the involvement of HDAC1 in the negative regulation of the Grp78 promoter not only by its induction in the presence of the HDAC inhibitors trichostatin A and MS-275, but also by exogenous overexpression and siRNA knockdown of specific HDACs. We present the results of chromatin immunoprecipitation analysis that reveals the binding of HDAC1 to the Grp78 promoter before but not after ER stress. Furthermore, overexpression of GRP78 confers resistance to HDAC inhibitor induced apoptosis in cancer cells and, conversely, suppression of GRP78 sensitizes them to HDAC inhibitor. These results define HDAC inhibitors as new agents that upregulate GRP78 without concomitantly inducing the ER or heat shock stress response, and suppression of GRP78 in tumors may provide a novel, adjunctive option to enhance anti-cancer therapies that utilize these compounds. PMID:19417144

  20. Autophagic degradation of peroxisomes in mammals.

    PubMed

    Katarzyna, Zientara-Rytter; Suresh, Subramani

    2016-04-15

    Peroxisomes are essential organelles required for proper cell function in all eukaryotic organisms. They participate in a wide range of cellular processes including the metabolism of lipids and generation, as well as detoxification, of hydrogen peroxide (H2O2). Therefore, peroxisome homoeostasis, manifested by the precise and efficient control of peroxisome number and functionality, must be tightly regulated in response to environmental changes. Due to the existence of many physiological disorders and diseases associated with peroxisome homoeostasis imbalance, the dynamics of peroxisomes have been widely examined. The increasing volume of reports demonstrating significant involvement of the autophagy machinery in peroxisome removal leads us to summarize current knowledge of peroxisome degradation in mammalian cells. In this review we present current models of peroxisome degradation. We particularly focus on pexophagy-the selective clearance of peroxisomes through autophagy. We also critically discuss concepts of peroxisome recognition for pexophagy, including signalling and selectivity factors. Finally, we present examples of the pathological effects of pexophagy dysfunction and suggest promising future directions.

  1. Autophagic degradation of peroxisomes in mammals

    PubMed Central

    Katarzyna, Zientara-Rytter; Suresh, Subramani

    2016-01-01

    Peroxisomes are essential organelles required for proper cell function in all eukaryotic organisms. They participate in a wide range of cellular processes including the metabolism of lipids and generation, as well as detoxification, of hydrogen peroxide. Therefore, peroxisome homeostasis, manifested by the precise and efficient control of peroxisome number and functionality, must be tightly regulated in response to environmental changes. Due to the existence of many physiological disorders and diseases associated with peroxisome homeostasis imbalance, the dynamics of peroxisomes have been widely examined. The increasing volume of reports demonstrating significant involvement of the autophagy machinery in peroxisome removal leads us to summarize current knowledge of peroxisome degradation in mammalian cells. In this review we present current models of peroxisome degradation. We particularly focus on pexophagy - the selective clearance of peroxisomes through autophagy. We also critically discuss concepts of peroxisome recognition for pexophagy, including signaling and selectivity factors. Finally, we present examples of the pathological effects of pexophagy dysfunction and suggest promising future directions. PMID:27068951

  2. Cellular signalling: the role of the peroxisome.

    PubMed

    Masters, C J

    1996-03-01

    This article reviews the role of the peroxisome in cellular signalling, with particular emphasis on the unique contributions of this organelle to the complex regulatory inter-relationships of cellular processes within the mammalian organism. Among the topics covered are the close alignments between the signalling systems governing peroxisome proliferation and those of the steroid hormone/thyroid hormone/vitamin D nuclear-receptor superfamily; the regulation of the permeability of the peroxisomal membrane; the involvements of lysophosphatidic acid as an intra- and inter-cellular messenger; the special role of the phosphatidylcholine cycle and its derivative messengers in relation to peroxisomal metabolism; peroxisomal contributions to the regulation of oxygen free radical levels in tissues and the significance of these radicals as second messengers; the evidence of peroxisomal influences on inter-cellular signalling from metabolic turnover studies; modifications of the regulatory significance of fatty acids by the peroxisome; the commonalities in metabolic relationships between the peroxisome and other cellular organelles; and regulatory shuttles associated with peroxisomal function. It is concluded that the peroxisome displays several significant interconnections with the cellular-signalling apparatus, that it is capable of imprinting a characteristic influence on the regulatory network in the cell, and that the contributions of this organelle deserve greater consideration in future investigations of cell-signalling phenomena.

  3. [Molecular mechanisms of peroxisome biogenesis in yeasts].

    PubMed

    Sibirnyĭ, A A

    2012-01-01

    Peroxisomes contain oxidases generating hydrogen peroxide, and catalase degrading this toxic compound. Another characteristic function of each eukaryotic peroxisome, from yeast to man, is fatty acid beta-oxidation. However, in peroxisomes a variety of other metabolic pathways are located. In fungi, peroxisomes contain enzymes involved in catabolism of unusual carbon and nitrogen sources (methanol, purines, D-amino acids, pipecolynic acid, sarcosine, glycolate, spermidine etc) as well as biosynthesis of lysine in yeasts and penicillin in mycelial fungi. Impairment of peroxisomal structure and functions causes many human disorders. The similar defects have been identified in yeast mutants defective in peroxisomal biogenesis. Peroxisomal biogenesis is actively studied during last two decades using uni- and multicellular model systems. It was observed that many aspects of peroxisomal biogenesis and proteins involved in this process display striking similarity between all eukaryotes, from yeasts to humans. Yeast is a convenient model system for this kind of research. Current review summarizes data on molecular events of peroxisomal biogenesis, functions of peroxine proteins, import of peroxisomal matrix and membrane proteins and on mechanisms of peroxisomedivision and inheritance. PMID:22642098

  4. The interaction between Helminthosporium carbonum and maize: Induced resistance and the role of an inhibitor

    SciTech Connect

    Cantone, F.A.

    1989-01-01

    Helminthosporium carbonum race 1 produces large, necrotic lesions on susceptible leaves of maize, whereas race 2 causes small, chlorotic flecks. Resistance to race 1 on susceptible leaves was induced when race 2 was inoculated for at least 10 h prior to a challenge inoculation with the pathogen and was manifest as a decrease in the number of appressoria and reduced penetration by race 1 conidia. Induced resistance was prevented or reversed when HC-toxin was added to challenge race 1 inoculum. The basis for protection appears to be a volatile, inhibitory compound produced by the host. This inhibitor was always associated with treatments that resulted in resistance, whereas no inhibitory activity was detected in diffusates from susceptible reactions. The appearance of inhibitor in diffusates coincided with the appearance of protection on the leaf. In addition to race 2 of H. carbonum, other fungi (H. victoriae, H. turcicum, and Alternaria) also induced production of the inhibitor as well as resistance to race 1. The inhibitor prevented the germination of conidia of all fungi tested. The growth of two phytopathogenic bacteria was also completely inhibited. Incorporation of {sup 3}H-leucine and {sup 14}C-uridine into protein and RNA, respectively, by conidia of H. carbonum was prevented within 15 min of exposure to inhibitor. In addition, respiration of conidia in inhibitor was reduced within 90 min to just 25% of the rate of conidia germinated in water. However, inhibitory activity of the diffusates was readily reversed when conidia were rinsed with water or when organic or amino acids were added to inhibited conidia. The addition of sodium acetate to race 2 and race 1 inocula resulted in lesion enlargement and also nullified inhibitory activity in vitro.

  5. PeroxisomeDB 2.0: an integrative view of the global peroxisomal metabolome

    PubMed Central

    Schlüter, Agatha; Real-Chicharro, Alejandro; Gabaldón, Toni; Sánchez-Jiménez, Francisca; Pujol, Aurora

    2010-01-01

    Peroxisomes are essential organelles that play a key role in redox signalling and lipid homeostasis. They contain a highly diverse enzymatic network among different species, mirroring the varied metabolic needs of the organisms. The previous PeroxisomeDB version organized the peroxisomal proteome of humans and Saccharomyces cerevisiae based on genetic and functional information into metabolic categories with a special focus on peroxisomal disease. The new release (http://www.peroxisomeDB.org) adds peroxisomal proteins from 35 newly sequenced eukaryotic genomes including fungi, yeasts, plants and lower eukaryotes. We searched these genomes for a core ensemble of 139 peroxisomal protein families and identified 2706 putative peroxisomal protein homologs. Approximately 37% of the identified homologs contained putative peroxisome targeting signals (PTS). To help develop understanding of the evolutionary relationships among peroxisomal proteins, the new database includes phylogenetic trees for 2386 of the peroxisomal proteins. Additional new features are provided, such as a tool to capture kinetic information from Brenda, CheBI and Sabio-RK databases and more than 1400 selected bibliographic references. PeroxisomeDB 2.0 is a freely available, highly interactive functional genomics platform that offers an extensive view on the peroxisomal metabolome across lineages, thus facilitating comparative genomics and systems analysis of the organelle. PMID:19892824

  6. PKC and PKA inhibitors reinstate morphine-induced behaviors in morphine tolerant mice.

    PubMed

    Smith, Forrest L; Javed, Ruby R; Smith, Paul A; Dewey, William L; Gabra, Bichoy H

    2006-12-01

    Male Swiss Webster mice exhibited antinociception, hypothermia and Straub tail 3h following a 75mg morphine pellet implantation. These signs disappeared by 72h, and the morphine-pelleted mice were indistinguishable from placebo-pelleted ones, although brain morphine concentrations ranged from 200 to 400ng/gm. We previously demonstrated that chemical inhibitors of protein kinase C (PKC) and A (PKA) are able to reverse morphine tolerance in acutely morphine-challenged mice. However, it was not known whether the reversal of tolerance was due to the interaction of kinase inhibitors with the morphine released from the pellet, the acutely injected morphine to challenge tolerant mice, or both. The present study aimed at determining the interaction between the PKC and PKA inhibitors and the morphine released "solely" from the pellet to reinstate the morphine-induced behavioral and physiological effects, 72h after implantation of morphine pellets. Placebo or 75mg morphine pellets were surgically implanted, and testing was conducted 72h later. Our results showed that the intracerebroventricular (i.c.v.) administration of the PKC inhibitors, bisindolylmaleimide I and Gö-6976 as well as the PKA inhibitors, 4-cyano-3-methylisoquinoline and KT-5720, restored the morphine-induced behaviors of antinociception, Straub tail and hypothermia in morphine-pelleted mice to the same extent observed 3h following the pellet implantation. The tail withdrawal and the hot plate reaction time expressed as percent maximum possible effect (%MPE) was increased to 80-100 and 41-90%, respectively, in PKC and PKA inhibitor-treated morphine tolerant mice compared to 2-10% in non-treated mice. Similarly, a significant hypothermia (1.3-4.0 degrees C decrease in body temperature) was detected in PKC and PKA inhibitor-treated morphine tolerant mice compared to an euthermic state in non-treated morphine tolerant mice. Finally, the Straub tail score was increased to 1.1-1.6 in PKC and PKA inhibitor

  7. Peroxisomes in Different Skeletal Cell Types during Intramembranous and Endochondral Ossification and Their Regulation during Osteoblast Differentiation by Distinct Peroxisome Proliferator-Activated Receptors

    PubMed Central

    Qian, Guofeng; Karnati, Srikanth; Baumgart-Vogt, Eveline

    2015-01-01

    Ossification defects leading to craniofacial dysmorphism or rhizomelia are typical phenotypes in patients and corresponding knockout mouse models with distinct peroxisomal disorders. Despite these obvious skeletal pathologies, to date no careful analysis exists on the distribution and function of peroxisomes in skeletal tissues and their alterations during ossification. Therefore, we analyzed the peroxisomal compartment in different cell types of mouse cartilage and bone as well as in primary cultures of calvarial osteoblasts. The peroxisome number and metabolism strongly increased in chondrocytes during endochondral ossification from the reserve to the hypertrophic zone, whereas in bone, metabolically active osteoblasts contained a higher numerical abundance of this organelle than osteocytes. The high abundance of peroxisomes in these skeletal cell types is reflected by high levels of Pex11β gene expression. During culture, calvarial pre-osteoblasts differentiated into secretory osteoblasts accompanied by peroxisome proliferation and increased levels of peroxisomal genes and proteins. Since many peroxisomal genes contain a PPAR-responsive element, we analyzed the gene expression of PPARɑ/ß/ɣ in calvarial osteoblasts and MC3T3-E1 cells, revealing higher levels for PPARß than for PPARɑ and PPARɣ. Treatment with different PPAR agonists and antagonists not only changed the peroxisomal compartment and associated gene expression, but also induced complex alterations of the gene expression patterns of the other PPAR family members. Studies in M3CT3-E1 cells showed that the PPARß agonist GW0742 activated the PPRE-mediated luciferase expression and up-regulated peroxisomal gene transcription (Pex11, Pex13, Pex14, Acox1 and Cat), whereas the PPARß antagonist GSK0660 led to repression of the PPRE and a decrease of the corresponding mRNA levels. In the same way, treatment of calvarial osteoblasts with GW0742 increased in peroxisome number and related gene expression

  8. The association of peroxisomes with the developing cell plate in dividing onion root cells depends on actin microfilaments and myosin.

    PubMed

    Collings, David A; Harper, John D I; Vaughn, Kevin C

    2003-12-01

    We have investigated changes in the distribution of peroxisomes through the cell cycle in onion ( Allium cepa L.) root meristem cells with immunofluorescence and electron microscopy, and in leek ( Allium porrum L.) epidermal cells with immunofluorescence and peroxisomal-targeted green fluorescent protein. During interphase and mitosis, peroxisomes distribute randomly throughout the cytoplasm, but beginning late in anaphase, they accumulate at the division plane. Initially, peroxisomes occur within the microtubule phragmoplast in two zones on either side of the developing cell plate. However, as the phragmoplast expands outwards to form an annulus, peroxisomes redistribute into a ring immediately inside the location of the microtubules. Peroxisome aggregation depends on actin microfilaments and myosin. Peroxisomes first accumulate in the division plane prior to the formation of the microtubule phragmoplast, and throughout cytokinesis, always co-localise with microfilaments. Microfilament-disrupting drugs (cytochalasin and latrunculin), and a putative inhibitor of myosin (2,3-butanedione monoxime), inhibit aggregation. We propose that aggregated peroxisomes function in the formation of the cell plate, either by regulating hydrogen peroxide production within the developing cell plate, or by their involvement in recycling of excess membranes from secretory vesicles via the beta-oxidation pathway. Differences in aggregation, a phenomenon which occurs in onion, some other monocots and to a lesser extent in tobacco BY-2 suspension cells, but which is not obvious in the roots of Arabidopsis thaliana (L.) Heynh., may reflect differences within the primary cell walls of these plants.

  9. Treatment of hypertension and renal injury induced by the angiogenesis inhibitor sunitinib: preclinical study.

    PubMed

    Lankhorst, Stephanie; Kappers, Mariëtte H W; van Esch, Joep H M; Smedts, Frank M M; Sleijfer, Stefan; Mathijssen, Ron H J; Baelde, Hans J; Danser, A H Jan; van den Meiracker, Anton H

    2014-12-01

    Common adverse effects of angiogenesis inhibition are hypertension and renal injury. To determine the most optimal way to prevent these adverse effects and to explore their interdependency, the following drugs were investigated in unrestrained Wistar Kyoto rats exposed to the angiogenesis inhibitor sunitinib: the dual endothelin receptor antagonist macitentan; the calcium channel blocker amlodipine; the angiotensin-converting enzyme inhibitor captopril; and the phosphodiesterase type 5 inhibitor sildenafil. Mean arterial pressure was monitored telemetrically. After 8 days, rats were euthanized and blood samples and kidneys were collected. In addition, 24-hour urine samples were collected. After sunitinib start, mean arterial pressure increased rapidly by ≈30 mm Hg. Coadministration of macitentan or amlodipine largely prevented this rise, whereas captopril or sildenafil did not. Macitentan, captopril, and sildenafil diminished the sunitinib-induced proteinuria and endothelinuria and glomerular intraepithelial protein deposition, whereas amlodipine did not. Changes in proteinuria and endothelinuria were unrelated. We conclude that in our experimental model, dual endothelin receptor antagonism and calcium channel blockade are suitable to prevent angiogenesis inhibition-induced hypertension, whereas dual endothelin receptor antagonism, angiotensin-converting enzyme inhibitor, and phosphodiesterase type 5 inhibition can prevent angiogenesis inhibition-induced proteinuria. Moreover, the variable response of hypertension and renal injury to different antihypertensive agents suggests that these side effects are, at least in part, unrelated.

  10. NOVEL ATYPICAL PKC INHIBITORS PREVENT VASCULAR ENDOTHELIAL GROWTH FACTOR-INDUCED BLOOD-RETINAL BARRIER DYSFUNCTION

    PubMed Central

    Titchenell, Paul M.; Lin, Cheng-Mao; Keil, Jason M.; Sundstrom, Jeffrey M.; Smith, Charles D.; Antonetti, David A.

    2013-01-01

    SYNOPSIS Pro-inflammatory cytokines and growth factors such as vascular endothelial growth factor (VEGF) contribute to the loss of the blood-retinal barrier (BRB) and subsequent macular edema in various retinal pathologies. VEGF signaling requires conventional PKC (PKCβ) activity; however, PKCβ inhibition only partially prevents VEGF-induced endothelial permeability and does not affect pro-inflammatory cytokine-induced permeability suggesting the involvement of alternative signaling pathways. Here, we provide evidence for the involvement of atypical protein kinase C (aPKC) signaling in VEGF-induced endothelial permeability and identify a novel class of inhibitors of aPKC that prevent BRB breakdown in vivo. Genetic and pharmacological manipulations of aPKC isoforms were used to assess their contribution to endothelial permeability in culture. A chemical library was screened using an in vitro kinase assay to identify novel small molecule inhibitors and further medicinal chemistry was performed to delineate a novel pharmacophore. We demonstrate that aPKC isoforms are both sufficient and required for VEGF-induced endothelial permeability. Furthermore, these specific, potent, non-competitive, small molecule inhibitors prevented VEGF-induced tight junction internalization and retinal endothelial permeability in response to VEGF in both primary culture and in rodent retina. These data suggest that aPKC inhibition with 2-amino-4-phenyl-thiophene derivatives may be developed to preserve the BRB in retinal diseases such as diabetic retinopathy or uveitis and the blood-brain barrier (BBB) in the presence of brain tumors. PMID:22721706

  11. [Cyclooxygenase inhibitors in some dietary vegetables inhibit platelet aggregation function induced by arachidonic acid].

    PubMed

    Wang, Xin-Hua; Shao, Dong-Hua; Liang, Guo-Wei; Zhang, Ru; Xin, Qin; Zhang, Tao; Cao, Qing-Yun

    2011-10-01

    The study was purposed to investigate whether the cyclooxygenase inhibitors from some dietary vegetables can inhibit platelet aggregation function by the arachidonic acid (AA). The vegetable juice was mixed with platelet rich plasma (PRP), and asprin was used as positive control. The maximum ratio of platelet aggregation induced by AA was measured on the aggregometer; heme and cyclooxygenase-1 (COX(1)) or cyclooxygenase-2 (COX(2)) were added to test tubes containing COX reaction buffer, the mixture was vortex-mixed and exposed to aspirin or vegetable juice, followed by addition of AA and then hydrochloric acid (1 mol/L) was added to stop the COX reaction, followed by chemical reduction with stannous chloride solution. The concentration of COX inhibitors was detected by the enzyme immunoassay kit; vegetable juice (aspirin as positive control) was mixed with whole blood, which was followed by the addition of AA, and then the reaction was stopped by adding indomethacin, centrifuged, then the supernatant was collected, and the plasma thromboxane B(2) (TXB(2)) was measured by radioimmunoassay. The results showed that spinach juice, garlic bolt juice, blanched garlic leave juice and Chinese leek juice could inhibit by 80% human platelet aggregation induced by AA. 4 kinds of vegetables were all found a certain amount of cyclooxygenase inhibitors, which COX(1) and COX(2) inhibitor concentrations of spinach were higher than that of aspirin; 4 vegetable juice could significantly reduce the human plasma concentrations of TXB(2) induced by AA (p < 0.05). It is concluded that 4 kinds of raw vegetables containing cyclooxygenase inhibitors inhibit the production of TXA(2) and thus hinder platelet aggregation. Raw spinach, garlic bolt, blanched garlic and chinese leek inhibit significantly AA-induced human platelet aggregation in vitro. 4 kinds of vegetables may have a good potential perspective of anti-platelet aggregation therapy or prevention of thrombosis.

  12. Treatment with Dimethyl Fumarate attenuates calcineurin inhibitor-induced Nephrotoxicity

    PubMed Central

    Takasu, Chie; Vaziri, Nosratola D.; Li, Shiri; Robles, Lourdes; Vo, Kelly; Takasu, Mizuki; Pham, Christine; Liu, Shuman; Farzaneh, Seyed H.; Foster, Clarence E; Stamos, Michael J; Ichii, Hirohito

    2014-01-01

    Background Cyclosporine A (CsA) is an immunosuppressive drug which has been widely used to prevent rejection following organ transplantation. However, its therapeutic use is limited by nephrotoxicity, in part mediated by oxidative stress. The present study aims to investigate the protective effects of Dimethyl Fumarate (DMF) on CsA-induced nephrotoxicity by enhancing the antioxidant defense system. Methods Male Sprague-Dawley rats were treated with CsA (n=8, 20 mg/kg/day i.p.) orCsA + DMF (n=7, 50 mg/kg/day p.o.) for 28 days. Renal function, histopathology, malondialdehyde (MDA), myeloperoxidase (MPO) levels and anti-oxidant enzyme expression were determined. Results DMF co-treatment ameliorated CsA-induced renal dysfunction as evidenced by significant decrease in serum creatinine (CsA 0.79 ± 0.02 mg/dl vs. CsA + DMF 0.62 ± 0.04 mg/dl, P=0.001) and urea (CsA 66.9 ± 0.4 mg/dl vs. CsA + DMF 53.3 ± 2.6 mg/dl, P<0.0001) levels, as well as improvement of creatinine clearance. DMF also significantly decreased serum MDA and renal tissue MDA and MPO contents. The protein expression of NQO-1, a major cellular anti-oxidant and detoxifying enzyme was significantly enhanced by DMF administration in kidney. Conclusions Administration of DMF has a protective potential against CsA nephrotoxicity. The protection afforded by DMF is mediated in part through inhibiting oxidative stress and inflammation and enhancing the antioxidant capacity. PMID:25710612

  13. Mitochondria are targets for peroxisome-derived oxidative stress in cultured mammalian cells.

    PubMed

    Wang, Bo; Van Veldhoven, Paul P; Brees, Chantal; Rubio, Noemí; Nordgren, Marcus; Apanasets, Oksana; Kunze, Markus; Baes, Myriam; Agostinis, Patrizia; Fransen, Marc

    2013-12-01

    Many cellular processes are driven by spatially and temporally regulated redox-dependent signaling events. Although mounting evidence indicates that organelles such as the endoplasmic reticulum and mitochondria can function as signaling platforms for oxidative stress-regulated pathways, little is known about the role of peroxisomes in these processes. In this study, we employ targeted variants of the genetically encoded photosensitizer KillerRed to gain a better insight into the interplay between peroxisomes and cellular oxidative stress. We show that the phototoxic effects of peroxisomal KillerRed induce mitochondria-mediated cell death and that this process can be counteracted by targeted overexpression of a select set of antioxidant enzymes, including peroxisomal glutathione S-transferase kappa 1, superoxide dismutase 1, and mitochondrial catalase. We also present evidence that peroxisomal disease cell lines deficient in plasmalogen biosynthesis or peroxisome assembly are more sensitive to KillerRed-induced oxidative stress than control cells. Collectively, these findings confirm and extend previous observations suggesting that disturbances in peroxisomal redox control and metabolism can sensitize cells to oxidative stress. In addition, they lend strong support to the ideas that peroxisomes and mitochondria share a redox-sensitive relationship and that the redox communication between these organelles is not only mediated by diffusion of reactive oxygen species from one compartment to the other. Finally, these findings indicate that mitochondria may act as dynamic receivers, integrators, and transmitters of peroxisome-derived mediators of oxidative stress, and this may have profound implications for our views on cellular aging and age-related diseases.

  14. An aqueous extract of Salacia oblonga root, a herb-derived peroxisome proliferator-activated receptor-alpha activator, by oral gavage over 28 days induces gender-dependent hepatic hypertrophy in rats.

    PubMed

    Rong, Xianglu; Kim, Moon Sun; Su, Ning; Wen, Suping; Matsuo, Yukimi; Yamahara, Johji; Murray, Michael; Li, Yuhao

    2008-06-01

    Activation of peroxisome proliferator-activated receptor (PPAR)-alpha by natural and synthetic chemicals induces hepatic hypertrophy. An aqueous extract of Salacia oblonga root (SOW) is an Ayurvedic medicine with anti-diabetic and anti-obesity properties. In the present study, it was found that SOW (100, 300 and 900mg/kg, once daily by oral gavage over a 28 day period) elicited dose-related increases in liver weight (LW) by 1.6%, 13.4% and 42.5%, respectively, and in the ratio of LW to body weight by 8.8%, 16.7% and 40.2%, respectively, in male rats. These effects were less pronounced in females. SOW selectively increased liver mass in male rats but Sudan red staining was not different, which indicates that hepatic lipid accumulation was similar in both genders. However, SOW even at the highest dosage did not influence serum ALT and AST activities in male or female rats. Moreover, SOW was found to activate PPAR-alpha in human hepatoma-derived HepG2 cells, as evidenced by the upregulation of PPAR-alpha and acyl-CoA oxidase mRNA expression. Thus, SOW-dependent PPAR-alpha activation may precede the development of the gender difference in hepatic hypertrophy; this process may be influenced by sex hormone status. PMID:18397819

  15. Peroxisome proliferator-activated receptor δ downregulates the expression of the receptor for advanced glycation end products and pro-inflammatory cytokines in the kidney of streptozotocin-induced diabetic mice.

    PubMed

    Liang, Yao-Jen; Chen, Siang-An; Jian, Jhih-Hao

    2011-05-18

    Activation of peroxisome proliferator-activated receptor δ (PPARδ) plays board beneficial effects in treating metabolic syndrome. The aim of this study is to examine whether PPARδ alters the expression of the receptor for advanced glycation end products (RAGE) and downstream pro-inflammatory cytokines in diabetic nephropathy. Streptozotocin-induced diabetic mice (STZ mice) were injected with a PPARδ agonist, L-165041 (5 μM/kg, intraperitoneal) once daily for 10 days and high glucose-treated cultured HEK cells were also used. After L-165041 treatment, serum TNFα, IL-6 and IL-1 levels were significantly decreased in STZ mice. RAGE mRNA and protein expression were both decreased by L-165041 in kidney tissues of STZ mice. The high glucose incubation increased NF-κB, RAGE and IL-6 expressions in HEK293 cells. These effects were inhibited by L-165041 and specific RAGE siRNA transfection. This study demonstrated that PPARδ may play a beneficial role in preventing diabetic nephropathy. Its downstream signaling may include RAGE and NF-κB pathway. Target on PPARδ will provide new meaningful therapies to patients with diabetic nephropathy.

  16. A novel histone deacetylase inhibitor Chidamide induces apoptosis of human colon cancer cells

    SciTech Connect

    Liu, Lin; Chen, Baoan; Qin, Shukui; Li, Suyi; He, Xiangming; Qiu, Shaomin; Zhao, Wei; Zhao, Hong

    2010-02-05

    Many studies have demonstrated that histone deacetylase (HDAC) inhibitors induce various tumor cells to undergo apoptosis, and such inhibitors have been used in different clinical trials against different human cancers. In this study, we designed and synthesized a novel HDAC inhibitor, Chidamide. We showed that Chidamide was able to increase the acetylation levels of histone H3 and to inhibit the PI3K/Akt and MAPK/Ras signaling pathways, which resulted in arresting colon cancer cells at the G1 phase of the cell cycle and promoting apoptosis. As a result, the proliferation of colon cancer cells was suppressed in vitro. Our data support the potential application of Chidamide as an anticancer agent in treating colon cancer. Future studies are needed to demonstrate its in vivo efficacy.

  17. Structural basis for induced-fit binding of Rho-kinase to the inhibitor Y-27632.

    PubMed

    Yamaguchi, Hiroto; Miwa, Yukiko; Kasa, Miyuki; Kitano, Ken; Amano, Mutsuki; Kaibuchi, Kozo; Hakoshima, Toshio

    2006-09-01

    Rho-kinase is a main player in the regulation of cytoskeletal events and a promising drug target in the treatment of both vascular and neurological disorders. Here we report the crystal structure of the Rho-kinase catalytic domain in complex with the specific inhibitor Y-27632. Comparison with the structure of PKA bound to this inhibitor revealed a potential induced-fit binding mode that can be accommodated by the phosphate binding loop. This binding mode resembles to that observed in the Rho-kinase-fasudil complex. A structural database search indicated that a pocket underneath the phosphate-binding loop is present that favors binding to a small aromatic ring. Introduction of such a ring group might spawn a new modification scheme of pre-existing protein kinase inhibitors for improved binding capability. PMID:16891330

  18. Aromatase Inhibitor-Induced Erythrocytosis in a Patient Undergoing Hormonal Treatment for Breast Cancer

    PubMed Central

    Yeruva, Sri Lakshmi Hyndavi; Ogbonna, Onyekachi Henry; Oneal, Patricia

    2015-01-01

    Aromatase inhibitors (AIs) are most commonly used for breast cancer patients with hormone receptor positive disease. Although the side effect profile of aromatase inhibitors is well known, including common side effects like arthralgia, bone pain, arthritis, hot flashes, and more serious problems like osteoporosis, we present a case of an uncommon side effect of these medications. We report the case of a postmenopausal woman on adjuvant hormonal therapy with anastrozole after completing definitive therapy for stage IIIB estrogen receptor-positive breast cancer, who was referred to hematology service for evaluation of persistent erythrocytosis. Primary and known secondary causes of polycythemia were ruled out. On further evaluation, we found that her erythrocytosis began after initiation of anastrozole and resolved after it was discontinued. We discuss the pathophysiology of aromatase inhibitor-induced erythrocytosis and reference of similar cases reported in the literature. PMID:26137331

  19. Pseudoceramide stimulates peroxisome proliferator-activated receptor-α expression in a murine model of atopic dermatitis: molecular basis underlying the anti-inflammatory effect and the preventive effect against steroid-induced barrier impairment.

    PubMed

    Lee, Sang Eun; Jung, Min Kyung; Oh, Seung Joon; Jeong, Se Kyoo; Lee, Seung Hun

    2015-11-01

    Topical pseudoceramides are successfully used in skin barrier repair therapy for atopic dermatitis (AD) and demonstrated to reduce the adverse effects of topical glucocorticoids (GC). However, the molecular mechanisms involved are not fully understood. We investigated whether PC-9S (myristoyl/palmitoyloxostearamide/arachamide MEA, Neopharm, Daejeon, Korea), one of the synthetic pseudoceramides, could stimulate peroxisome proliferator-activated receptor (PPAR)α expression in a hapten [oxazolone (oxa)]-induced AD murine model (oxa-AD mice) and subsequently improved permeability barrier, reduced inflammation, and increased antimicrobial peptides (AMPs) expression. Normal hairless mice and oxa-AD mice were topically treated twice daily with either PC-9S-containing physiologic lipid mixture (PLM), vehicle (PLM), or PPARα agonist for 4 days. Topical PC-9S significantly increased PPARα expression in mouse epidermis in vivo and in oxa-AD mice skin comparable with PPARα agonist. Topical PC-9S-containing PLM significantly reduced basal trans-epidermal water loss (TEWL), surface pH, and mast cell infiltrates and prevented the decline of AMPs expression in oxa-AD mice, which were abrogated by PPARα antagonist. Then, oxa-AD mice were treated with super-potent topical GC twice daily for 4 days with or without PC-9S co-applications. Co-treatment with PC-9S-containing PLM suppressed GC-induced increase in basal TEWL, epidermal thinning, reduced loricrin expression, and impaired barrier recovery and these effects were attenuated by PPARα antagonist. Collectively, our findings suggest that pseudoceramide PC-9S-induced stimulation of PPARα expression provides a new mechanism by which pseudoceramides show anti-inflammatory property, improve the permeability and antimicrobial barrier function, and prevent the negative effects of topical GC.

  20. Histone deacetylase inhibitor-induced cancer stem cells exhibit high pentose phosphate pathway metabolism

    PubMed Central

    Debeb, Bisrat G.; Lacerda, Lara; Larson, Richard; Wolfe, Adam R.; Krishnamurthy, Savitri; Reuben, James M.; Ueno, Naoto T.; Gilcrease, Michael; Woodward, Wendy A.

    2016-01-01

    Purpose We recently demonstrated that histone deacetylase (HDAC) inhibitors can “reprogram” differentiated triple-negative breast cancer cells to become quiescent stem-like cancer cells. We hypothesized that the metabolic state of such cells differs from that of their differentiated progeny. Results In untreated cells, glucose uptake was higher in ALDH+ cells than in ALDH− cells (p = 0.01) but lactate production was not different; treating ALDH− or ALDH+ cells with VA or SAHA similarly increased glucose uptake without changing lactate production but upregulated G6PD, a rate-limiting enzyme in pentose phosphate pathway metabolism. NADPH production was higher in HDAC inhibitor-treated stem-like cells than in vehicle-treated cells (p < 0.05). Two G6PD inhibitors, 6-aminonicotinamide and dehydroepiandrosterone, decreased mammosphere formation efficiency and ALDH activity and 6-aminonicotinamide reduced the VA-induced increase in ALDH+ cells. Finally, patients expressing high G6PD mRNA had significantly worse overall survival (p < 0.001), and patients with high G6PD protein showed a similar trend towards worse disease-specific survival (p = 0.06). Methods Glucose consumption, lactate and NADPH production, and reactive oxygen species generation were compared in aldehyde dehydrogenase (ALDH)-positive and –negative cells in the presence or absence of the HDAC inhibitors valproic acid (VA) or suberoylanilide hydroxamic acid (SAHA). Glucose-6-phosphate dehydrogenase (G6PD) expression was evaluated in a tissue microarray from 94 patients with node-positive invasive breast carcinoma and in two publically available databases and correlated with overall survival. Conclusions Energy metabolism in HDAC inhibitor-induced stem-like cancer cells differed sharply from that of differentiated cell types. HDAC inhibitor-induced dedifferentiation promoted metabolic reprogramming into the pentose phosphate pathway, which is targeted effectively by G6PD inhibition. These findings

  1. PPAR-γ Impairment Alters Peroxisome Functionality in Primary Astrocyte Cell Cultures

    PubMed Central

    Di Cesare Mannelli, Lorenzo; Zanardelli, Matteo; Micheli, Laura; Ghelardini, Carla

    2014-01-01

    Peroxisomes provide glial cells with protective functions against the harmful effects of H2O2 on neurons and peroxisome impairment results in nervous lesions. Agonists of the γ-subtype of the Peroxisome-Proliferator-Activated-Receptors (PPAR) have been proposed as neuroprotective agents in neurodegenerative disorders. Nevertheless, the role of PPAR-γ alterations in pathophysiological mechanisms and the relevance of peroxisome functions in the PPAR-γ effects are not yet clear. In a primary cell culture of rat astrocytes, the irreversible PPAR-γ antagonist GW9662 concentration-dependently decreased the activity of catalase, the most important antioxidant defense enzyme in peroxisomes. Catalase functionality recovered in a few days and the PPAR-γ agonist rosiglitazone promoted reversal of enzymatic damage. The reversible antagonist G3335 reduced both the activity and expression of catalase in a rosiglitazone-prevented manner. G3335 reduced also the glutathione reductase expression, indicating that enzyme involved in glutathione regeneration was compromised. Neither the PPAR-α target gene Acyl-Coenzyme-A-oxidase-1 nor the mitochondrial detoxifying enzyme NADH:ubiquinone-oxidoreductase (NDFUS3) was altered by PPAR-γ inhibition. In conclusion, PPAR-γ inhibition induced impairment of catalase in astrocytes. A general decrease of the antioxidant defenses of the cell suggests that a PPAR-γ hypofunction could participate in neurodegenerative mechanisms through peroxisomal damage. This series of experiments could be a useful model for studying compounds able to restore peroxisome functionality. PMID:24729976

  2. Peroxisome deficient invertebrate and vertebrate animal models

    PubMed Central

    Van Veldhoven, Paul P.; Baes, Myriam

    2013-01-01

    Although peroxisomes are ubiquitous organelles in all animal species, their importance for the functioning of tissues and organs remains largely unresolved. Because peroxins are essential for the biogenesis of peroxisomes, an obvious approach to investigate their physiological role is to inactivate a Pex gene or to suppress its translation. This has been performed in mice but also in more primitive organisms including D. melanogaster, C. elegans, and D. rerio, and the major findings and abnormalities in these models will be highlighted. Although peroxisomes are generally not essential for embryonic development and organogenesis, a generalized inactivity of peroxisomes affects lifespan and posthatching/postnatal growth, proving that peroxisomal metabolism is necessary for the normal maturation of these organisms. Strikingly, despite the wide variety of model organisms, corresponding tissues are affected including the central nervous system and the testis. By inactivating peroxisomes in a cell type selective way in the brain of mice, it was also demonstrated that peroxisomes are necessary to prevent neurodegeneration. As these peroxisome deficient model organisms recapitulate pathologies of patients affected with peroxisomal diseases, their further analysis will contribute to the elucidation of still elusive pathogenic mechanisms. PMID:24319432

  3. Why do peroxisomes associate with the cytoskeleton?

    PubMed

    Neuhaus, Alexander; Eggeling, Christian; Erdmann, Ralf; Schliebs, Wolfgang

    2016-05-01

    Attachment of peroxisomes to cytoskeleton and movement along microtubular filaments and actin cables are essential and highly regulated processes enabling metabolic efficiency, biogenesis, maintenance and inheritance of this dynamic cellular compartment. Several peroxisome-associated proteins have been identified, which mediate interaction with motor proteins, adaptor proteins or other constituents of the cytoskeleton. It appears that there is a species-specific complexity of protein-protein interactions required to control directional movement and arresting. An open question is why some proteins with a specific role in peroxisomal protein import have an additional function in the regulation of cytoskeleton binding and motility of peroxisomes.

  4. An ER-peroxisome tether exerts peroxisome population control in yeast.

    PubMed

    Knoblach, Barbara; Sun, Xuejun; Coquelle, Nicolas; Fagarasanu, Andrei; Poirier, Richard L; Rachubinski, Richard A

    2013-09-11

    Eukaryotic cells compartmentalize biochemical reactions into membrane-enclosed organelles that must be faithfully propagated from one cell generation to the next. Transport and retention processes balance the partitioning of organelles between mother and daughter cells. Here we report the identification of an ER-peroxisome tether that links peroxisomes to the ER and ensures peroxisome population control in the yeast Saccharomyces cerevisiae. The tether consists of the peroxisome biogenic protein, Pex3p, and the peroxisome inheritance factor, Inp1p. Inp1p bridges the two compartments by acting as a molecular hinge between ER-bound Pex3p and peroxisomal Pex3p. Asymmetric peroxisome division leads to the formation of Inp1p-containing anchored peroxisomes and Inp1p-deficient mobile peroxisomes that segregate to the bud. While peroxisomes in mother cells are not released from tethering, de novo formation of tethers in the bud assists in the directionality of peroxisome transfer. Peroxisomes are thus stably maintained over generations of cells through their continued interaction with tethers.

  5. The Synergistic Enhancement of Cloning Efficiency in Individualized Human Pluripotent Stem Cells by Peroxisome Proliferative-activated Receptor-γ (PPARγ) Activation and Rho-associated Kinase (ROCK) Inhibition.

    PubMed

    Kajabadi, Nasim-Sadat; Ghoochani, Ali; Peymani, Maryam; Ghaedi, Kamran; Kiani-Esfahani, Abbas; Hashemi, Motahareh-Sadat; Nasr-Esfahani, Mohammad Hossein; Baharvand, Hossein

    2015-10-23

    Although human pluripotent stem cells (hPSCs) provide valuable sources for regenerative medicine, their applicability is dependent on obtaining both suitable up-scaled and cost effective cultures. The Rho-associated kinase (ROCK) inhibitor Y-27632 permits hPSC survival upon dissociation; however, cloning efficiency is often still low. Here we have shown that pioglitazone, a selective peroxisome proliferative-activated receptor-γ agonist, along with Y-27632 synergistically diminished dissociation-induced apoptosis and increased cloning efficiency (2-3-fold versus Y-27632) without affecting pluripotency of hPSCs. Pioglitazone exerted its positive effect by inhibition of glycogen synthase kinase (GSK3) activity and enhancement of membranous β-catenin and E-cadherin proteins. These effects were reversed by GW-9662, an irreversible peroxisome proliferative-activated receptor-γ antagonist. This novel setting provided a step toward hPSC manipulation and its biomedical applications.

  6. Pathophysiology of visual disorders induced by phosphodiesterase inhibitors in the treatment of erectile dysfunction

    PubMed Central

    Moschos, Marilita M; Nitoda, Eirini

    2016-01-01

    Aim The aim of this review was to summarize the ocular action of the most common phosphodiesterase (PDE) inhibitors used for the treatment of erectile dysfunction and the subsequent visual disorders. Method This is a literature review of several important articles focusing on the pathophysiology of visual disorders induced by PDE inhibitors. Results PDE inhibitors have been associated with ocular side effects, including changes in color vision and light perception, blurred vision, transient alterations in electroretinogram (ERG), conjunctival hyperemia, ocular pain, and photophobia. Sildenafil and tadalafil may induce reversible increase in intraocular pressure and be involved in the development of non-arteritic ischemic optic neuropathy. Reversible idiopathic serous macular detachment, central serous chorioretinopathy, and ERG disturbances have been related to the significant impact of sildenafil and tadalafil on retinal perfusion. Discussion So far, PDE inhibitors do not seem to cause permanent toxic effects on chorioretinal tissue and photoreceptors. However, physicians should write down any visual symptom observed during PDE treatment and refer the patients to ophthalmologists. PMID:27799745

  7. Pulsed EPR Characterization of HIV-1 Protease Conformational Sampling and Inhibitor-Induced Population Shifts

    PubMed Central

    Liu, Zhanglong; Casey, Thomas M.; Blackburn, Mandy E.; Huang, Xi; Pham, Linh; de Vera, Ian Mitchelle S.; Carter, Jeffrey D.; Kear-Scott, Jamie L.; Veloro, Angelo M.; Galiano, Luis; Fanucci, Gail E.

    2015-01-01

    The conformational landscape of HIV-1 protease (PR) can be experimentally characterized by pulsed-EPR double electron-electron resonance (DEER). For this characterization, nitroxide spin labels are attached to an engineered cysteine residue in the flap region of HIV-1 PR. DEER distance measurements from spin-labels contained within each flap of the homodimer provide a detailed description of the conformational sampling of apo-enzyme as well as induced conformational shifts as a function inhibitor binding. The distance distribution profiles are further interpreted in terms of a conformational ensemble scheme that consists of four unique states termed “curled/tucked”, “closed”, “semi-open” and “wide-open” conformations. Reported here are the DEER results for a drug-resistant variant clinical isolate sequence, V6, in the presence of FDA approved protease inhibitors (PIs) as well as a non-hydrolyzable substrate mimic, CaP2. Results are interpreted in the context of the current understanding of the relationship between conformational sampling, drug resistance, and kinetic efficiency of HIV-1PR as derived from previous DEER and kinetic data for a series of HIV-1PR constructs that contain drug-pressure selected mutations or natural polymorphisms. Specifically, these collective results support the notion that inhibitor-induced closure of the flaps correlates with inhibitor efficiency and drug resistance. This body of work also suggests DEER as a tool for studying conformational sampling in flexible enzymes as it relates to function. PMID:26489725

  8. Unique presentations of epidermal growth factor receptor inhibitor-induced papulopustular eruption related to bacterial superinfection.

    PubMed

    Wiznia, Lauren Elyse; Choi, Jennifer Nam

    2013-01-01

    Epidermal growth factor receptor (EGFR) inhibitors have been reported to induce numerous cutaneous side effects, the most notable of which is a papulopustular eruption on the face, scalp, and central chest. The typical presentation consists of inflamed papules, often with pustules, favoring a seborrheic distribution. The pustules of the EGFR inhibitor-induced papulopustular eruption are commonly sterile but bacterial superinfection is not uncommon. We report two unique presentations of the papulopustular eruption that were found to be associated with Staphylococcus aureus superinfection. One patient presented with an abrupt onset of nearly confluent red plaques on the cheeks, forehead, chin, and neck, with innumerable studded pinpoint pustules. The other patient had a long-standing untreated papulopustular eruption on the scalp, which resulted in widespread erythema, large thick plaques of serous crust, pustular exudate, and associated alopecia. Both patients quickly resolved with non-tetracycline oral antibiotics combined with topical steroid treatment. PMID:23552005

  9. A sycamore cell wall polysaccharide and a chemically related tomato leaf polysaccharide possess similar proteinase inhibitor-inducing activities.

    PubMed

    Ryan, C A; Bishop, P; Pearce, G

    1981-09-01

    A large pectic polysaccharide, called rhamnogalacturonan I, that is solubilized by a fungal endo-alpha-1,4-polygalacturonase from the purified walls of suspension-cultured sycamore cells possesses proteinase inhibitor-inducing activity similar to that of the proteinase inhibitor-inducing factor, a pectic-like oligosaccharide fraction isolated from tomato leaves. This suggests that the proteinase inhibitor-inducing activity resides in particular polysaccharide fragments which can be released when plant cell walls are exposed to appropriate enzyme degradation as a result of either wounding or pest attack.

  10. An experimental study on amelioration of dyslipidemia-induced atherosclesis by Clematichinenoside through regulating Peroxisome proliferator-activated receptor-α mediated apolipoprotein A-I, A-II and C-III.

    PubMed

    Liu, Chao; Guo, Qianqian; Lu, Mengchen; Li, Yunman

    2015-08-15

    Prevention or amelioration the prevalence of atherosclerosis has been an effective strategy in the management of cardiovascular diseases. The aim of the study was to scrutinize the effect of Clematichinenoside (AR) on dyslipidemia-induced atherosclerosis and explore its capability on expression of Peroxisome proliferator-activated receptor-α (PPAR-alpha), apolipoprotein A-I (APOA1) and A-II (APOA2), and suppression of apolipoprotein C-III (APOC3) genes and proteins. In the present study, we investigated atherosclerosis effect of AR using a combination of high-fat diet and balloon injury model in rabbits. The levels of biochemical indicators were evaluated in plasma, liver and HepG2 cells using immunoassay technology. In order to expose the underlying mechanism, we evaluated the regulation of PPAR-alpha, APOA1, APOA2 and APOC3 expressions by AR, and we further evaluated the interactions between them after transfection with shRNA (shPPAR-alpha) and, the action of PPAR-alpha in HepG2 cells. We could find that AR markedly promoted the PPAR-alpha transfer from cytoplasm to nucleus which resulted in the alteration of APOA1, APOA2 and APOC3 expressions in HepG2 cells. Moreover, AR significantly reduced total cholesterol, triglycerides and low-density lipoprotein cholesterol (LDL-C) levels, and elevated high-density lipoprotein cholesterol (HDL-C) level, which play an important role in dyslipidemia-induced atherosclerosis. In conclusion, AR ameliorated atherosclerosis via the regulation of hepatic lipid metabolism, and AR also contributed to the activation of PPAR-alpha, APOA1, APOA2 and APOC3. Therefore, AR could be a potential therapeutic agent in the treatment of atherosclerosis.

  11. A Nanoconjugate Apaf-1 Inhibitor Protects Mesothelial Cells from Cytokine-Induced Injury

    PubMed Central

    Santamaría, Beatriz; Benito-Martin, Alberto; Ucero, Alvaro Conrado; Aroeira, Luiz Stark; Reyero, Ana; Vicent, María Jesús; Orzáez, Mar; Celdrán, Angel; Esteban, Jaime; Selgas, Rafael; Ruíz-Ortega, Marta; Cabrera, Manuel López; Egido, Jesús; Pérez-Payá, Enrique; Ortiz, Alberto

    2009-01-01

    Background Inflammation may lead to tissue injury. We have studied the modulation of inflammatory milieu-induced tissue injury, as exemplified by the mesothelium. Peritoneal dialysis is complicated by peritonitis episodes that cause loss of mesothelium. Proinflammatory cytokines are increased in the peritoneal cavity during peritonitis episodes. However there is scarce information on the modulation of cell death by combinations of cytokines and on the therapeutic targets to prevent desmesothelization. Methodology Human mesothelial cells were cultured from effluents of stable peritoneal dialysis patients and from omentum of non-dialysis patients. Mesothelial cell death was studied in mice with S. aureus peritonitis and in mice injected with tumor necrosis factor alpha and interferon gamma. Tumor necrosis factor alpha and interferon gamma alone do not induce apoptosis in cultured mesothelial cells. By contrast, the cytokine combination increased the rate of apoptosis 2 to 3-fold over control. Cell death was associated with the activation of caspases and a pancaspase inhibitor prevented apoptosis. Specific caspase-8 and caspase-3 inhibitors were similarly effective. Co-incubation with both cytokines also impaired mesothelial wound healing in an in vitro model. However, inhibition of caspases did not improve wound healing and even impaired the long-term recovery from injury. By contrast, a polymeric nanoconjugate Apaf-1 inhibitor protected from apoptosis and allowed wound healing and long-term recovery. The Apaf-1 inhibitor also protected mesothelial cells from inflammation-induced injury in vivo in mice. Conclusion Cooperation between tumor necrosis factor alpha and interferon gamma contributes to mesothelial injury and impairs the regenerative capacity of the monolayer. Caspase inhibition attenuates mesothelial cell apoptosis but does not facilitate regeneration. A drug targeting Apaf-1 allows protection from apoptosis as well as regeneration in the course of

  12. The Calpain Inhibitor MDL28170 Induces the Expression of Apoptotic Markers in Leishmania amazonensis Promastigotes

    PubMed Central

    Marinho, Fernanda A.; Gonçalves, Keyla C. S.; Oliveira, Simone S. C.; Gonçalves, Diego S.; Matteoli, Filipe P.; Seabra, Sergio H.; Oliveira, Ana Carolina S.; Bellio, Maria; Oliveira, Selma S.; Souto-Padrón, Thaïs; d'Avila-Levy, Claudia M.; Santos, André L. S.; Branquinha, Marta H.

    2014-01-01

    Background Human cutaneous leishmaniasis is caused by distinct species, including Leishmania amazonensis. Treatment of cutaneous leishmaniasis is far from satisfactory due to increases in drug resistance and relapses, and toxicity of compounds to the host. As a consequence for this situation, the development of new leishmanicidal drugs and the search of new targets in the parasite biology are important goals. Methodology/Principal Findings In this study, we investigated the mechanism of death pathway induced by the calpain inhibitor MDL28170 on Leishmania amazonensis promastigote forms. The combined use of different techniques was applied to contemplate this goal. MDL28170 treatment with IC50 (15 µM) and two times the IC50 doses induced loss of parasite viability, as verified by resazurin assay, as well as depolarization of the mitochondrial membrane, which was quantified by JC-1 staining. Scanning and transmission electron microscopic images revealed drastic alterations on the parasite morphology, some of them resembling apoptotic-like death, including cell shrinking, surface membrane blebs and altered chromatin condensation pattern. The lipid rearrangement of the plasma membrane was detected by Annexin-V labeling. The inhibitor also induced a significant increase in the proportion of cells in the sub-G0/G1 phase, as quantified by propidium iodide staining, as well as genomic DNA fragmentation, detected by TUNEL assay. In cells treated with MDL28170 at two times the IC50 dose, it was also possible to observe an oligonucleossomal DNA fragmentation by agarose gel electrophoresis. Conclusions/Significance The data presented in the current study suggest that MDL28170 induces apoptotic marker expression in promastigotes of L. amazonensis. Altogether, the results described in the present work not only provide a rationale for further exploration of the mechanism of action of calpain inhibitors against trypanosomatids, but may also widen the investigation of the

  13. Effect of ethylene action inhibitors upon wound-induced gene expression in tomato pericarp

    SciTech Connect

    Henstrand, J.M.; Handa, A.K. )

    1989-09-01

    The contribution of wound-ethylene to wound-induced gene expression was investigated in unripe tomato pericarp using inhibitors of ethylene action. Wounded unripe tomato pericarp was treated with 2,5-norbornadiene or silver thiosulfate to inhibit specifically the induction of ethylene-dependent mRNA species. Poly(A){sup +} RNAs isolated from these tissues after 12 hours of wounding were translated in vitro in a rabbit reticulocyte lysate system and ({sup 35}S)methionine-labeled polypeptides were compared to unwounded controls after separation by one and two-dimensional polyacrylamide gel electrophoresis. Results show that mechanical wounding induces a dramatic shift in gene expression (over 50 mRNA species) but expression of less than 15% of these genes is affected by the treatment with ethylene action inhibitors. A selective decrease in mRNAs coding for a 37 kilodalton doublet and 75 kilodalton polypeptides is observed in 2,5-norbornadiene and silver thiosulfate treated wounded pericarp. Levels of hydroxyproline-rich glycoprotein mRNAs induced in wounded tissue were not influenced by inhibitors of ethylene action.

  14. T cell tolerance induced by histone deacetylase inhibitor is mediated by P21cip1.

    PubMed

    Gilbert, Kathleen M; Boger, Susan R; Price, Peter; Fifer, E Kim

    2005-01-01

    MEB [n-butyrate 2-(4-morpholinyl) ethyl butyrate hydrochloride], a histone deacetylase inhibitor and G1 blocker, has been shown to induce unresponsiveness in antigen-activated Th1 cells. MEB was tested for here for its ability to inactivate naive alloantigen-specific T cells from DBA/2 and C57BL/10 mice. Since T cells from these two strains of mice have been shown to differ in their cell cycle regulation, it we hoped that this comparison would provide information concerning the role of cycle regulatory proteins in mediating MEB-induced T cell unresponsiveness. MEB inhibited proliferation in a one-way mixed lymphocyte reaction (MLR) in which spleen cells from DBA/2 mice (H-2d) or C57BL/10 mice (H-2b) were stimulated with spleen cells from C57BL/10 or DBA/2 mice, respectively. C57BL/10 responder T cells isolated from the MEB-treated primary MLR remained unresponsive to alloantigen following restimulation in a secondary MLR that did not contain MEB. T cells from DBA/2 mice were less sensitive to MEB-induced unresponsiveness and required a longer exposure or pretreatment with IL-2 to become tolerant. In all cases responsiveness to MEB-induced tolerance in the alloantigen-stimulated T cells corresponded with the levels of the cyclin-dependent kinase inhibitor p21cip1. Additional experiments showed that T cells from p21cip1-deficient mice, unlike T cells from p21cip1 wild-type littermates, were resistant to MEB-induced tolerance. These results underscore the role of p21cip1 in mediating T cell tolerance induced by the histone deacetylase inhibitor MEB.

  15. Genetic variation and relationships of constitutive and herbivore-induced glucosinolates, trypsin inhibitors, and herbivore resistance in Brassica rapa.

    PubMed

    Cipollini, Donald F; Busch, Jeremiah W; Stowe, Kirk A; Simms, Ellen L; Bergelson, Joy

    2003-02-01

    We examined genetic variation in inducibility and in constitutive and herbivore-induced levels of glucosinolates, trypsin inhibitors, and resistance to herbivory in families of Brassica rapa originating from a wild population. We also examined phenotypic and genetic correlations among absolute levels of these traits in control and induced plants. We grew seedlings of 10 half-sib families in pairs in pots, and exposed one plant per pair to folivory by Trichoplusia ni larvae. Two days later, we sampled all plants for total glucosinolate and trypsin inhibitor levels and examined the preference and consumption by T. ni larvae of previously damaged (induced) and undamaged (control) plants. There was no significant variation among sire families in the induction of glucosinolates or trypsin inhibitors by T. ni feeding. Total glucosinolate levels in either control or induced plants did not vary by family. In contrast, trypsin inhibitor levels in both control and induced plants varied significantly by family. Trichoplusia ni fed less on induced plants than on control plants in the bioassay, but neither the induction of resistance by prior T. ni feeding nor absolute levels of damage done to control and induced plants varied significantly by sire family. Temporal blocking strongly affected trypsin inhibitor levels and the response of some families in the bioassays. There were no significant phenotypic or genetic correlations of levels of glucosinolates or trypsin inhibitors with each other or with damage in either control or induced plants. Overall, these results suggest that in the B. rapa population that we studied, both total glucosinolate content and biological resistance to herbivory by T. ni was nonvariable and almost universally inducible by prior T. ni feeding. In contrast, control and induced levels of trypsin inhibitors varied genetically and have the capacity to respond to future selection imposed by herbivores. However, the role of these defenses in constitutive

  16. Comparison of hepatic peroxisome proliferative effect and its implication for hepatocarcinogenicity of phthalate esters, di(2-ethylhexyl) phthalate, and di(2-ethylhexyl) adipate with a hypolipidemic drug.

    PubMed Central

    Reddy, J K; Reddy, M K; Usman, M I; Lalwani, N D; Rao, M S

    1986-01-01

    Peroxisome proliferation is inducible in hepatocytes of rodent and nonrodent species by structurally dissimilar hypolipidemic drugs and certain phthalate ester plasticizers. The induction of peroxisome proliferation appears to be a tissue specific response limited largely to the hepatocyte. Peroxisome proliferation is associated with increases in the activity of the H2O2-generating peroxisomal fatty acid beta-oxidation system and in the amount of peroxisome proliferation-associated 80,000 MW polypeptide (PPA-80). Chronic administration of these non-DNA damaging and nonmutagenic peroxisome proliferators to rats and mice results in the development of hepatocellular carcinomas. Comparative morphometric and biochemical data from rats treated with varying dose levels of ciprofibrate, a hypolipidemic drug, and di(2-ethylhexyl) phthalate, and di(2-ethylhexyl) adipate, the widely used plasticizers, indicate that the hepatocarcinogenic potency of these agents is correlatable with their ability to induce peroxisome proliferation, peroxisomal beta-oxidation and PPA-80. Available evidence strongly favors the role of peroxisome proliferation-associated oxidative stress in the induction of liver tumors by peroxisome proliferators. Images FIGURE 3. FIGURE 4. FIGURE 5. FIGURE 7. FIGURE 10. A FIGURE 10. B PMID:3709457

  17. Depressor effect of chymase inhibitor in mice with high salt-induced moderate hypertension.

    PubMed

    Devarajan, Sankar; Yahiro, Eiji; Uehara, Yoshinari; Habe, Shigehisa; Nishiyama, Akira; Miura, Shin-ichiro; Saku, Keijiro; Urata, Hidenori

    2015-12-01

    The aim of the present study was to determine whether long-term high salt intake in the drinking water induces hypertension in wild-type (WT) mice and whether a chymase inhibitor or other antihypertensive drugs could reverse the increase of blood pressure. Eight-week-old male WT mice were supplied with drinking water containing 2% salt for 12 wk (high-salt group) or high-salt drinking water plus an oral chymase inhibitor (TPC-806) at four different doses (25, 50, 75, or 100 mg/kg), captopril (75 mg/kg), losartan (100 mg/kg), hydrochlorothiazide (3 mg/kg), eplerenone (200 mg/kg), or amlodipine (6 mg/kg). Control groups were given normal water with or without the chymase inhibitor. Blood pressure and heart rate gradually showed a significant increase in the high-salt group, whereas a dose-dependent depressor effect of the chymase inhibitor was observed. There was also partial improvement of hypertension in the losartan- and eplerenone-treated groups but not in the captopril-, hydrochlorothiazide-, and amlodipine-treated groups. A high salt load significantly increased chymase-dependent ANG II-forming activity in the alimentary tract. In addition, the relative contribution of chymase to ANG II formation, but not actual average activity, showed a significant increase in skin and skeletal muscle, whereas angiotensin-converting enzyme-dependent ANG II-forming activity and its relative contribution were reduced by high salt intake. Plasma and urinary renin-angiotensin system components were significantly increased in the high-salt group but were significantly suppressed in the chymase inhibitor-treated group. In conclusion, 2% salt water drinking for 12 wk caused moderate hypertension and activated the renin-angiotensin system in WT mice. A chymase inhibitor suppressed both the elevation of blood pressure and heart rate, indicating a definite involvement of chymase in salt-sensitive hypertension.

  18. Transcription inhibitors prevent amnesia induced by NMDA antagonist-mediated impairment of memory reconsolidation.

    PubMed

    Nikitin, Vladimir P; Solntseva, Svetlana V; Shevelkin, Alexey V

    2016-09-01

    Recent studies report that long-term memory retrieval can induce memory reconsolidation, and impairment of this reconsolidation might lead to amnesia. Previously, we found that reconsolidation of a conditioned food aversion memory could be disrupted by translation inhibitors for up to 3 h following a reconsolidation event, thus inducing amnesia. We examined the role of transcription processes in the induction of amnesia in the land snail, Helix lucorum. It received N-methyl-D-aspartate (NMDA) glutamate receptor antagonist and transcription inhibitor 2 days after learning in a neutral context environment; it was then transferred to the learning context followed by reminder with conditioned food stimulus. NMDA receptor blockade, followed by a reminder session, impaired reconsolidation of an aversive memory. Simultaneous administration of an NMDA receptor antagonist and a transcription inhibitor prior to reminder of an aversive event prevented amnesia induction. In contrast, when a transcription inhibitor alone was injected prior to a reminder session, the blockade had no effect on memory. We found that transcription inhibition 0-6 h after amnesia induction suppressed memory loss, but this suppression was lost when inhibitors were administered 9 h after amnesia. Thus, amnesia is likely dependent on transcription processes within a 9-h time window. We can hypothesize that amnesia induction initiates synthesis of specific mRNAs and proteins; furthermore, these events occur within specific time-dependent windows. Our findings could prove useful for the analysis of amnesia formation and for the development of possible ways to prevent memory loss associated with various diseases and injuries in animals and humans. PMID:26742927

  19. Further studies of auxin and ACC induced feminization in the cucumber plant using ethylene inhibitors

    NASA Technical Reports Server (NTRS)

    Takahashi, H.; Jaffe, M. J.

    1984-01-01

    The present study was designed to establish the role of an essential hormone controlling sex expression in cucumber. A potent anti-ethylene agent, AgNO3, completely inhibited pistillate flower formation caused by IAA, ACC or ethephon. Inhibitors of ethylene biosynthesis, AVG and CoCl2 also suppressed feminization due to exogenous IAA or ACC. Though AVG also suppressed ethephon-induced feminization, this may be due to the second effect of AVG rather than the effect on ACC biosynthesis. These results confirm that ethylene is a major factor regulating feminization and that exogenous auxin induces pistillate flower formation through its stimulation of ethylene production, rather than ACC production.

  20. Novel phosphodiesterase 4 inhibitor T-440 reverses and prevents human bronchial contraction induced by allergen.

    PubMed

    Fujii, K; Kohrogi, H; Iwagoe, H; Hamamoto, J; Hirata, N; Goto, E; Kawano, O; Wada, K; Yamagata, S; Ando, M

    1998-01-01

    To study the roles of phosphodiesterase (PDE) 4 in the human airways, we examined the effect of the novel PDE4 inhibitor T-440 in the isolated human bronchus. T-440 inhibited PDE4 extracted from human bronchial smooth muscle. IC50 values for the effect of T-440, rolipram (a PDE4 inhibitor) and theophylline on PDE4 activity of the bronchial tissues were 0.08 microM, 2 microM and > 100 microM, respectively. T-440 (10(-6) M to 10(-5) M) and aminophylline (3.3 x 10(-5) M) significantly reversed the 10(-5) M histamine-induced contraction, the efficacy of 10(-6) M T-440 being almost the same as that of 3.3 x 10(-5) M aminophylline. T-440 (10(-6) M to 10(-5) M) and aminophylline (3.3 x 10(-5) M) significantly reversed the 10(-4) M ACh-induced contraction. But their reversal effects on the ACh-induced contraction were weaker than those on the histamine-induced contraction. T-440 (10(-5) M) significantly reversed the contraction induced by allergen in passively sensitized bronchi. The efficacy of the reversal effect of T-440 (10(-5) M) was significantly higher than that of aminophylline (10(-5) M). T-440 and aminophylline significantly relaxed the basal tension, but pretreatment with T-440 or aminophylline did not significantly prevent histamine- or ACh-induced contraction. In contrast, both T-440 (10(-5) M) and aminophylline (3.3 x 10(-5) M) prevented the contraction induced by allergen, which suggests that PDE4 inhibitor inhibits the release of chemical mediators probably from bronchial mast cells in the allergic response. T-440 (10(-6) M to 10(-5) M) caused the accumulation of cAMP at the concentration that relaxed histamine-induced contraction. Thus selective PDE4 inhibitor is a candidate for the treatment of asthma. PMID:9435174

  1. Effects of inhibitors on 1-methyladenine induced maturation of starfish oocytes

    NASA Astrophysics Data System (ADS)

    Lee, Harold H.; Xu, Quanhan

    1986-12-01

    1-methladenine (1-MA) induces starfish oocytes maturation via surface reaction followed by the appearance of a cytoplasmic maturation factor which in turn induces germinal vesicle breakdown (GVBD) to resume meiosis. Cellular mechanisms involved in GVBD were investigated by microinjection of metabolic inhibitors. Colchicine (Co) inhibited maturation, cytochalasin-B (CB) delayed GVBD and actinomycin-D-(Act-D) and puromycin (Pu) had no effect. It appears that the microtubule and the microfilament systems are associated with the nuclear membrane dissolution during the process of oocyte maturation of starfish.

  2. Characterization of a novel component of the peroxisomal protein import apparatus using fluorescent peroxisomal proteins.

    PubMed Central

    Kalish, J E; Keller, G A; Morrell, J C; Mihalik, S J; Smith, B; Cregg, J M; Gould, S J

    1996-01-01

    Fluorescent peroxisomal probes were developed by fusing green fluorescent protein (GFP) to the matrix peroxisomal targeting signals PTS1 and PTS2, as well as to an integral peroxisomal membrane protein (IPMP). These proteins were used to identify and characterize novel peroxisome assembly (pas) mutants in the yeast Pichia pastoris. Mutant cells lacking the PAS10 gene mislocalized both PTS1-GFP and PTS2-GFP to the cytoplasm but did incorporate IPMP-GFP into peroxisome membranes. Similar distributions were observed for endogenous peroxisomal matrix and membrane proteins. While peroxisomes from translocation-competent pas mutants sediment in sucrose gradients at the density of normal peroxisomes, >98% of peroxisomes from pas10 cells migrated to a much lower density and had an extremely low ratio of matrix:membrane protein. These data indicate that Pas10p plays an important role in protein translocation across the peroxisome membrane. Consistent with this hypothesis, we find that Pas10p is an integral protein of the peroxisome membrane. In addition, Pas10p contains a cytoplasmically-oriented C3HC4 zinc binding domain that is essential for its biological activity. Images PMID:8670828

  3. Arginine improves peroxisome functioning in cells from patients with a mild peroxisome biogenesis disorder

    PubMed Central

    2013-01-01

    Background Zellweger spectrum disorders (ZSDs) are multisystem genetic disorders caused by a lack of functional peroxisomes, due to mutations in one of the PEX genes, encoding proteins involved in peroxisome biogenesis. The phenotypic spectrum of ZSDs ranges from an early lethal form to much milder presentations. In cultured skin fibroblasts from mildly affected patients, peroxisome biogenesis can be partially impaired which results in a mosaic catalase immunofluorescence pattern. This peroxisomal mosaicism has been described for specific missense mutations in various PEX genes. In cell lines displaying peroxisomal mosaicism, peroxisome biogenesis can be improved when these are cultured at 30°C. This suggests that these missense mutations affect the folding and/or stability of the encoded protein. We have studied if the function of mutant PEX1, PEX6 and PEX12 can be improved by promoting protein folding using the chemical chaperone arginine. Methods Fibroblasts from three PEX1 patients, one PEX6 and one PEX12 patient were cultured in the presence of different concentrations of arginine. To determine the effect on peroxisome biogenesis we studied the following parameters: number of peroxisome-positive cells, levels of PEX1 protein and processed thiolase, and the capacity to β-oxidize very long chain fatty acids and pristanic acid. Results Peroxisome biogenesis and function in fibroblasts with mild missense mutations in PEX1, 6 and 12 can be improved by arginine. Conclusion Arginine may be an interesting compound to promote peroxisome function in patients with a mild peroxisome biogenesis disorder. PMID:24016303

  4. Localization of the Tomato Bushy Stunt Virus Replication Protein p33 Reveals a Peroxisome-to-Endoplasmic Reticulum Sorting PathwayW⃞

    PubMed Central

    McCartney, Andrew W.; Greenwood, John S.; Fabian, Marc R.; White, K. Andrew; Mullen, Robert T.

    2005-01-01

    Tomato bushy stunt virus (TBSV), a positive-strand RNA virus, causes extensive inward vesiculations of the peroxisomal boundary membrane and formation of peroxisomal multivesicular bodies (pMVBs). Although pMVBs are known to contain protein components of the viral membrane-bound RNA replication complex, the mechanisms of protein targeting to peroxisomal membranes and participation in pMVB biogenesis are not well understood. We show that the TBSV 33-kD replication protein (p33), expressed on its own, targets initially from the cytosol to peroxisomes, causing their progressive aggregation and eventually the formation of peroxisomal ghosts. These altered peroxisomes are distinct from pMVBs; they lack internal vesicles and are surrounded by novel cytosolic vesicles that contain p33 and appear to be derived from evaginations of the peroxisomal boundary membrane. Concomitant with these changes in peroxisomes, p33 and resident peroxisomal membrane proteins are relocalized to the peroxisomal endoplasmic reticulum (pER) subdomain. This sorting of p33 is disrupted by the coexpression of a dominant-negative mutant of ADP-ribosylation factor1, implicating coatomer in vesicle formation at peroxisomes. Mutational analysis of p33 revealed that its intracellular sorting is also mediated by several targeting signals, including three peroxisomal targeting elements that function cooperatively, plus a pER targeting signal resembling an Arg-based motif responsible for vesicle-mediated retrieval of escaped ER membrane proteins from the Golgi. These results provide insight into virus-induced intracellular rearrangements and reveal a peroxisome-to-pER sorting pathway, raising new mechanistic questions regarding the biogenesis of peroxisomes in plants. PMID:16284309

  5. Peroxisomes in brain development and function☆

    PubMed Central

    Berger, Johannes; Dorninger, Fabian; Forss-Petter, Sonja; Kunze, Markus

    2016-01-01

    Peroxisomes contain numerous enzymatic activities that are important for mammalian physiology. Patients lacking either all peroxisomal functions or a single enzyme or transporter function typically develop severe neurological deficits, which originate from aberrant development of the brain, demyelination and loss of axonal integrity, neuroinflammation or other neurodegenerative processes. Whilst correlating peroxisomal properties with a compilation of pathologies observed in human patients and mouse models lacking all or individual peroxisomal functions, we discuss the importance of peroxisomal metabolites and tissue- and cell type-specific contributions to the observed brain pathologies. This enables us to deconstruct the local and systemic contribution of individual metabolic pathways to specific brain functions. We also review the recently discovered variability of pathological symptoms in cases with unexpectedly mild presentation of peroxisome biogenesis disorders. Finally, we explore the emerging evidence linking peroxisomes to more common neurological disorders such as Alzheimer’s disease, autism and amyotrophic lateral sclerosis. This article is part of a Special Issue entitled: Peroxisomes edited by Ralf Erdmann. PMID:26686055

  6. Proliferation and fission of peroxisomes - An update.

    PubMed

    Schrader, Michael; Costello, Joseph L; Godinho, Luis F; Azadi, Afsoon S; Islinger, Markus

    2016-05-01

    In mammals, peroxisomes perform crucial functions in cellular metabolism, signalling and viral defense which are essential to the health and viability of the organism. In order to achieve this functional versatility peroxisomes dynamically respond to molecular cues triggered by changes in the cellular environment. Such changes elicit a corresponding response in peroxisomes, which manifests itself as a change in peroxisome number, altered enzyme levels and adaptations to the peroxisomal structure. In mammals the generation of new peroxisomes is a complex process which has clear analogies to mitochondria, with both sharing the same division machinery and undergoing a similar division process. How the regulation of this division process is integrated into the cell's response to different stimuli, the signalling pathways and factors involved, remains somewhat unclear. Here, we discuss the mechanism of peroxisomal fission, the contributions of the various division factors and examine the potential impact of post-translational modifications, such as phosphorylation, on the proliferation process. We also summarize the signalling process and highlight the most recent data linking signalling pathways with peroxisome proliferation.

  7. Peroxisomal targeting signals in green algae.

    PubMed

    Shinozaki, Akiko; Sato, Nagisa; Hayashi, Yasuko

    2009-03-01

    Peroxisomal enzymatic proteins contain targeting signals (PTS) to enable their import into peroxisomes. These targeting signals have been identified as PTS1 and PTS2 in mammalian, yeast, and higher plant cells; however, no PTS2-like amino acid sequences have been observed in enzymes from the genome database of Cyanidiochyzon merolae (Bangiophyceae), a primitive red algae. In studies on the evolution of PTS, it is important to know when their sequences came to be the peroxisomal targeting signals for all living organisms. To this end, we identified a number of genes in the genome database of the green algae Chlamydomonas reinhardtii, which contains amino acid sequences similar to those found in plant PTS. In order to determine whether these sequences function as PTS in green algae, we expressed modified green fluorescent proteins (GFP) fused to these putative PTS peptides under the cauliflower mosaic virus 35S promoter. To confirm whether granular structures containing GFP-PTS fusion proteins accumulated in the peroxisomes of Closterium ehrenbergii, we observed these cells after the peroxisomes were stained with 3, 3'-diaminobenzidine. Our results confirm that the GFP-PTS fusion proteins indeed accumulated in the peroxisomes of these green algae. These findings suggest that the peroxisomal transport system for PTS1 and PTS2 is conserved in green algal cells and that our fusion proteins can be used to visualize peroxisomes in live cells.

  8. Next-generation proteasome inhibitor MLN9708 sensitizes breast cancer cells to doxorubicin-induced apoptosis

    PubMed Central

    Wang, Hao; Yu, Yang; Jiang, Zheng; Cao, Wen-Ming; Wang, Zhenyu; Dou, Jun; Zhao, Yanling; Cui, Yunfu; Zhang, Hong

    2016-01-01

    Doxorubicin (Dox), one of the most effective chemotherapy drug for cancer treatment, is limited by its severe side effects and chemoresistance. Dox induces DNA damage and leads to significant proteomic changes in the cancer cells, which makes the ubiquitin-proteasome system a potential target to enhance the efficacy of Dox therapy. The unsuccessful clinical trials of proteasome inhibitor PS-341 (bortezomib) in solid tumors led to the invention of MLN9708 (ixazomib), an orally bioavailable next-generation proteasome inhibitor with improved pharmacokinetic and pharmacodynamic features. In this preclinical study, we used eight human breast cancer cell lines, which represent the major molecular subtypes of breast cancer, to validate the cytotoxic effects of MLN9708, alone and in combination with Dox. We found that MLN9708 had cytotoxic effects, induced autophagy and MKP-1 expression, and enhanced Dox-induced apoptosis in these cell lines. MLN9708 also enhanced Dox-induced JNK and p38 phosphorylation and inhibited Dox-induced IκBα degradation. Our in vitro results suggest that MLN9708 has antitumor effects in breast cancer and can sensitize breast cancer cells to Dox treatment. This promising combination may be an effective and feasible therapeutic option for treating breast cancer and warrants clinical validation. PMID:27217076

  9. Translation inhibitors induce formation of cholesterol ester-rich lipid droplets.

    PubMed

    Suzuki, Michitaka; Ohsaki, Yuki; Tatematsu, Tsuyako; Shinohara, Yuki; Maeda, Takashi; Cheng, Jinglei; Fujimoto, Toyoshi

    2012-01-01

    Lipid droplets (LDs) in non-adipocytes contain triglycerides (TG) and cholesterol esters (CE) in variable ratios. TG-rich LDs are generated when unsaturated fatty acids are administered, but the conditions that induce CE-rich LD formation are less well characterized. In the present study, we found that protein translation inhibitors such as cycloheximide (CHX) induced generation of CE-rich LDs and that TIP47 (perilipin 3) was recruited to the LDs, although the expression of this protein was reduced drastically. Electron microscopy revealed that LDs formed in CHX-treated cells possess a distinct electron-dense rim that is not found in TG-rich LDs, whose formation is induced by oleic acid. CHX treatment caused upregulation of mTORC1, but the CHX-induced increase in CE-rich LDs occurred even when rapamycin or Torin1 was given along with CHX. Moreover, the increase in CE was seen in both wild-type and autophagy-deficient Atg5-null mouse embryonic fibroblasts, indicating that mTORC1 activation and suppression of autophagy are not necessary to induce the observed phenomenon. The results showed that translation inhibitors cause a significant change in the lipid ester composition of LDs by a mechanism independent of mTORC1 signaling and autophagy. PMID:22879956

  10. Inhibition of peroxisome fission, but not mitochondrial fission, increases yeast chronological lifespan.

    PubMed

    Lefevre, Sophie D; Kumar, Sanjeev; van der Klei, Ida J

    2015-01-01

    Mitochondria are key players in aging and cell death. It has been suggested that mitochondrial fragmentation, mediated by the Dnm1/Fis1 organelle fission machinery, stimulates aging and cell death. This was based on the observation that Saccharomyces cerevisiae Δdnm1 and Δfis1 mutants show an enhanced lifespan and increased resistance to cell death inducers. However, the Dnm1/Fis1 fission machinery is also required for peroxisome division. Here we analyzed the significance of peroxisome fission in yeast chronological lifespan, using yeast strains in which fission of mitochondria was selectively blocked. Our data indicate that the lifespan extension caused by deletion of FIS1 is mainly due to a defect in peroxisome fission and not caused by a block in mitochondrial fragmentation. These observations are underlined by our observation that deletion of FIS1 does not lead to lifespan extension in yeast peroxisome deficient mutant cells.

  11. Apoptosis and antitumor effects induced by the combination of an mTOR inhibitor and an autophagy inhibitor in human osteosarcoma MG63 cells

    PubMed Central

    HORIE, RYOSUKE; NAKAMURA, OSAMU; YAMAGAMI, YOSHIKI; MORI, MASAKI; NISHIMURA, HIDEKI; FUKUOKA, NATSUKO; YAMAMOTO, TETSUJI

    2016-01-01

    The inhibition of the mammalian target of rapamycin (mTOR) signaling pathway promotes the initiation of autophagy. Although it remains under debate whether chemotherapy-induced autophagy in tumor cells is a protective response or is invoked to promote cell death, recent studies indicate that autophagy is a self-defense mechanism of cancer cells that are subjected to antitumor agents and that blocking autophagy can trigger apoptosis. The aim of this study was to examine the effects of rapamycin, an mTOR inhibitor, on MG63 osteosarcoma cells. We further examined whether the combination of rapamycin and the small molecule inhibitor of autophagy Spautin-1 (specific and potent autophagy inhibitor-1) enhanced the rapamycin-induced apoptosis in MG63 cells. We examined the effects of rapamycin treatment on cell proliferation, phosphorylation of mTOR pathway components, and autophagy by western blot analysis. Furthermore, we examined the effects of rapamycin with or without Spautin-1 on the induction of apoptosis by western blot analysis and immunohistochemical staining. We found that rapamycin inhibited cell proliferation and decreased the phosphorylation of mTOR pathway components in MG63 cells. Rapamycin induced the apoptosis of MG63 cells, and this apoptosis was enhanced by Spautin-1. It was considered that Spautin-1 suppressed the protective mechanism induced by rapamycin in tumor cells and induced apoptosis. Therefore, the combination of an mTOR inhibitor and an autophagy inhibitor may be effective in the treatment of osteosarcoma because it effectively induces the apoptotic pathway. PMID:26530936

  12. Cell Death Inducing Microbial Protein Phosphatase Inhibitors--Mechanisms of Action.

    PubMed

    Kleppe, Rune; Herfindal, Lars; Døskeland, Stein Ove

    2015-10-01

    Okadaic acid (OA) and microcystin (MC) as well as several other microbial toxins like nodularin and calyculinA are known as tumor promoters as well as inducers of apoptotic cell death. Their intracellular targets are the major serine/threonine protein phosphatases. This review summarizes mechanisms believed to be responsible for the death induction and tumor promotion with focus on the interdependent production of reactive oxygen species (ROS) and activation of Ca(2+)/calmodulin kinase II (CaM-KII). New data are presented using inhibitors of specific ROS producing enzymes to curb nodularin/MC-induced liver cell (hepatocyte) death. They indicate that enzymes of the arachidonic acid pathway, notably phospholipase A2, 5-lipoxygenase, and cyclooxygenases, may be required for nodularin/MC-induced (and presumably OA-induced) cell death, suggesting new ways to overcome at least some aspects of OA and MC toxicity. PMID:26506362

  13. Natural furocoumarins as inducers and inhibitors of cytochrome P450 1A1 in rat hepatocytes.

    PubMed

    Baumgart, Annette; Schmidt, Melanie; Schmitz, Hans-Joachim; Schrenk, Dieter

    2005-02-15

    Furocoumarins are natural plant constituents present in medicinal plants and in a variety of foods such as grapefruit juice. They are phototoxic and act as potent inhibitors of drug metabolism. We have investigated the interaction of four furocoumarins angelicin, bergamottin, isopimpinellin, and 8-methoxypsoralen with the expression and activity of aryl hydrocarbon receptor (AhR)-regulated CYP1A1 in rat hepatocytes in primary culture, both in the presence and absence of light. In intact hepatocytes pretreated with 2,3,7,8-tetrachlorodibenzo-p-dioxin and in microsomes isolated thereof, all furocoumarins tested acted as potent inhibitors of CYP1A1 activity bergamottin being the most potent inhibitor in microsomes with an IC(50) of 10 nM in the presence and 60 nM in the absence of light. 8-Methoxypsoralen and angelicin led to a significant induction of CYP1A1 mRNA in hepatocytes, while all furocoumarins except bergamottin increased xenobiotic-responsive element-driven reporter gene expression in transfected H4IIE rat hepatoma cells when light was excluded. Furthermore, all furocoumarins tested induced the expression of endogenous, immunoreactive CYP1A1 protein, primarily in the dark. In conclusion, our results demonstrate that individual furocoumarins present in food and medicinal plants can interfere with AhR-regulated CYP1A1 expression and activity in at least three major ways, i.e., (i) act as highly potent inhibitors of the catalytic activity of CYP1A1 both in the presence and absence of light, (ii) induce CYP1A1 gene expression in the absence of light via activation of the AhR, and (iii) induce CYP1A1 gene expression without activation of the AhR.

  14. The intracellular Ca(2+)-pump inhibitors thapsigargin and cyclopiazonic acid induce stress proteins in mammalian chondrocytes.

    PubMed

    Cheng, T C; Benton, H P

    1994-07-15

    Primary cultures of mammalian articular chondrocytes respond to treatment with the intracellular Ca(2+)-pump inhibitors thapsigargin (TG) and cyclopiazonic acid by specific changes in protein synthesis consistent with a stress response. Two-dimensional gel electrophoresis of newly synthesized proteins confirmed that the response was consistent with the induction of glucose-regulated proteins. The effects of low-dose TG (10 nM), measured by changes in [35S]methionine labelling of newly synthesized proteins, can first be observed by 10 h and are maximal by 24 h. The pattern of changes induced by TG is shared with cyclopiazonic acid, but effects of both perturbants differ significantly from changes induced by heat shock. Upon removal of TG, normal protein synthesis is restored by 48 h. Immunoblots showed increased concentrations of the stress proteins HSP90, HSP72/73 and HSP60 in chondrocytes treated with TG, but induction of newly synthesized heat-shock proteins by TG was not apparent on [35S]methionine-labelled gels. The alterations in protein synthesis induced by Ca(2+)-pump inhibitors were unaffected by BAPTA-AM loading, which clamped cytosolic Ca2+ at resting levels. We conclude that inhibition of intracellular Ca(2+)-pump activity can elicit a stress response, which has important implications for the interpretation of chronic use of Ca(2+)-pump inhibitors. In particular, the activation of the cellular shock response should be considered in interpreting the regulation of protein synthesis and cell survival by Ca(2+)-pump inhibitors such as TG. PMID:8043004

  15. Electron transport chain inhibitors induce microglia activation through enhancing mitochondrial reactive oxygen species production.

    PubMed

    Ye, Junli; Jiang, Zhongxin; Chen, Xuehong; Liu, Mengyang; Li, Jing; Liu, Na

    2016-01-15

    Reactive oxygen species (ROS) are believed to be mediators of excessive microglial activation, yet the resources and mechanism are not fully understood. Here we stimulated murine microglial BV-2 cells and primary microglial cells with different inhibitors of electron transport chain (ETC), rotenone, thenoyltrifluoroacetone (TTFA), antimycin A, and NaN3 to induce mitochondrial ROS production and we observed the role of mitochondrial ROS in microglial activation. Our results showed that ETC inhibitors resulted in significant changes in cell viability, microglial morphology, cell cycle arrest and mitochondrial ROS production in a dose-dependent manner in both primary cultural microglia and BV-2 cell lines. Moreover, ETC inhibitors, especially rotenone and antimycin A stimulated secretion of interleukin 1β (IL-1β), interleukin 6 (IL-6), interleukin 12 (IL-12) and tumor necrosis factor α (TNF-α) by microglia with marked activation of mitogen-activated proteinkinases (MAPKs) and nuclear factor κB (NF-κB), which could be blocked by specific inhibitors of MAPK and NF-κB and mitochondrial antioxidants, Mito-TEMPO. Taken together, our results demonstrated that inhibition of mitochondrial respiratory chain in microglia led to production of mitochondrial ROS and therefore may activate MAPK/NF-кB dependent inflammatory cytokines release in microglia, which indicated that mitochondrial-derived ROS were contributed to microglial activation.

  16. Inhibitor of apoptosis signal-regulating kinase 1 protects against acetaminophen-induced liver injury

    SciTech Connect

    Xie, Yuchao; Ramachandran, Anup; Breckenridge, David G.; Liles, John T.; Lebofsky, Margitta; Farhood, Anwar; Jaeschke, Hartmut

    2015-07-01

    Metabolic activation and oxidant stress are key events in the pathophysiology of acetaminophen (APAP) hepatotoxicity. The initial mitochondrial oxidative stress triggered by protein adduct formation is amplified by c-jun-N-terminal kinase (JNK), resulting in mitochondrial dysfunction and ultimately cell necrosis. Apoptosis signal-regulating kinase 1 (ASK1) is considered the link between oxidant stress and JNK activation. The objective of the current study was to assess the efficacy and mechanism of action of the small-molecule ASK1 inhibitor GS-459679 in a murine model of APAP hepatotoxicity. APAP (300 mg/kg) caused extensive glutathione depletion, JNK activation and translocation to the mitochondria, oxidant stress and liver injury as indicated by plasma ALT activities and area of necrosis over a 24 h observation period. Pretreatment with 30 mg/kg of GS-459679 almost completely prevented JNK activation, oxidant stress and injury without affecting the metabolic activation of APAP. To evaluate the therapeutic potential of GS-459679, mice were treated with APAP and then with the inhibitor. Given 1.5 h after APAP, GS-459679 was still protective, which was paralleled by reduced JNK activation and p-JNK translocation to mitochondria. However, GS-459679 treatment was not more effective than N-acetylcysteine, and the combination of GS-459679 and N-acetylcysteine exhibited similar efficacy as N-acetylcysteine monotherapy, suggesting that GS-459769 and N-acetylcysteine affect the same pathway. Importantly, inhibition of ASK1 did not impair liver regeneration as indicated by PCNA staining. In conclusion, the ASK1 inhibitor GS-459679 protected against APAP toxicity by attenuating JNK activation and oxidant stress in mice and may have therapeutic potential for APAP overdose patients. - Highlights: • Two ASK1 inhibitors protected against acetaminophen-induced liver injury. • The ASK1 inhibitors protect when used as pre- or post-treatment. • Protection by ASK1 inhibitor is

  17. Pioglitazone ameliorates behavioral, biochemical and cellular alterations in quinolinic acid induced neurotoxicity: possible role of peroxisome proliferator activated receptor-Upsilon (PPARUpsilon) in Huntington's disease.

    PubMed

    Kalonia, Harikesh; Kumar, Puneet; Kumar, Anil

    2010-08-01

    Emerging evidence indicates that PPARUpsilon activators attenuate neurodegeneration and related complications. Therefore, the present study focused on the neuroprotective potential of pioglitazone against quinolinic acid (QUIN) induced neurotoxicity. Intrastriatal (unilaterally) administration of QUIN significantly altered body weight and motor function (locomotor activity, rotarod and beam walk performance). Further, QUIN treatment significantly caused oxidative damage (increased lipid peroxidation, nitrite concentration and depleted endogenous antioxidant defense enzymes), altered mitochondrial enzyme complex (I, II and IV) activities and TNF-alpha level as compared to sham treated animals. Pioglitazone (10, 20 and 40mg/kg, p.o.) treatment significantly improved body weight and motor functions, oxidative defense. Further, pioglitazone treatment restored mitochondrial enzyme complex activity as well as TNF-alpha level as compared to QUIN treated group. While Bisphenol A diglycidyl ether (BADGE) (15mg/kg), PPARUpsilon antagonist significantly reversed the protective effect of the pioglitazone (40mg/kg) in the QUIN treated animals. Further, pioglitazone treatment significantly attenuated the striatal lesion volume in QUIN treated animals, suggesting a role for the PPARUpsilon pathway in QUIN induced neurotoxicity. Altogether, this evidence indicates that PPARUpsilon activation by pioglitazone attenuated QUIN induced neurotoxicity in animals and which could be an important therapeutic avenue to ameliorate Huntington like symptoms. PMID:20450929

  18. The peroxisome proliferator-activated receptor α agonist, AZD4619, induces alanine aminotransferase-1 gene and protein expression in human, but not in rat hepatocytes: Correlation with serum ALT levels.

    PubMed

    Thulin, Petra; Bamberg, Krister; Buler, Marcin; Dahl, Björn; Glinghammar, Björn

    2016-09-01

    Alanine aminotransferase (ALT) in serum is the standard biomarker for liver injury. We have previously described a clinical trial with a novel selective peroxisome proliferator-activated receptor α (PPARα) agonist (AZD4619), which unexpectedly caused increased serum levels of ALT in treated individuals without any other evidence of liver injury. We pinpointed a plausible mechanism through which AZD4619 could increase serum ALT levels; namely through the PPARα-specific activation of the human ALT1 gene at the transcriptional level. In the present study, we present data from the preceding rat toxicity study, demonstrating that AZD4619 had no effect on rat serum ALT activity levels, and further experiments were performed to elucidate the mechanisms responsible for this species-related difference. Our results revealed that AZD4619 increased ALT1 protein expression in a dose-dependent manner in human, but not in rat primary hepatocytes. Cloning of the human and rat ALT1 promoters into luciferase vectors confirmed that AZD4619 induced only the human, but not the rat ALT1 gene promoter in a dose-dependent manner. In PPARα-GAL4 reporter gene assays, AZD4619 was >100-fold more potent on the human vs. rat PPARα levels, explaining the differences in induction of the ALT1 gene between the species at the concentration range tested. These data demonstrate the usefulness of the human and rat ALT1 reporter gene assays for testing future drug candidates at the preclinical stage. In drug discovery projects, these assays elucidate whether elevations in ALT levels observed in vivo or in the clinic are due to metabolic effects rather than a toxic event in the liver. PMID:27430334

  19. A Novel Peroxisome Proliferator-activated Receptor (PPAR)α Agonist and PPARγ Antagonist, Z-551, Ameliorates High-fat Diet-induced Obesity and Metabolic Disorders in Mice*

    PubMed Central

    Shiomi, Yoshihiro; Yamauchi, Toshimasa; Iwabu, Masato; Okada-Iwabu, Miki; Nakayama, Ryo; Orikawa, Yuki; Yoshioka, Yoshichika; Tanaka, Koichiro; Ueki, Kohjiro; Kadowaki, Takashi

    2015-01-01

    A novel peroxisome proliferator-activated receptor (PPAR) modulator, Z-551, having both PPARα agonistic and PPARγ antagonistic activities, has been developed for the treatment of obesity and obesity-related metabolic disorders. We examined the effects of Z-551 on obesity and the metabolic disorders in wild-type mice on the high-fat diet (HFD). In mice on the HFD, Z-551 significantly suppressed body weight gain and ameliorated insulin resistance and abnormal glucose and lipid metabolisms. Z-551 inhibited visceral fat mass gain and adipocyte hypertrophy, and reduced molecules involved in fatty acid uptake and synthesis, macrophage infiltration, and inflammation in adipose tissue. Z-551 increased molecules involved in fatty acid combustion, while reduced molecules associated with gluconeogenesis in the liver. Furthermore, Z-551 significantly reduced fasting plasma levels of glucose, triglyceride, free fatty acid, insulin, and leptin. To elucidate the significance of the PPAR combination, we examined the effects of Z-551 in PPARα-deficient mice and those of a synthetic PPARγ antagonist in wild-type mice on the HFD. Both drugs showed similar, but weaker effects on body weight, insulin resistance and specific events provoked in adipose tissue compared with those of Z-551 as described above, except for lack of effects on fasting plasma triglyceride and free fatty acid levels. These findings suggest that Z-551 ameliorates HFD-induced obesity, insulin resistance, and impairment of glucose and lipid metabolisms by PPARα agonistic and PPARγ antagonistic activities, and therefore, might be clinically useful for preventing or treating obesity and obesity-related metabolic disorders such as insulin resistance, type 2 diabetes, and dyslipidemia. PMID:25907553

  20. A Novel Peroxisome Proliferator-activated Receptor (PPAR)α Agonist and PPARγ Antagonist, Z-551, Ameliorates High-fat Diet-induced Obesity and Metabolic Disorders in Mice.

    PubMed

    Shiomi, Yoshihiro; Yamauchi, Toshimasa; Iwabu, Masato; Okada-Iwabu, Miki; Nakayama, Ryo; Orikawa, Yuki; Yoshioka, Yoshichika; Tanaka, Koichiro; Ueki, Kohjiro; Kadowaki, Takashi

    2015-06-01

    A novel peroxisome proliferator-activated receptor (PPAR) modulator, Z-551, having both PPARα agonistic and PPARγ antagonistic activities, has been developed for the treatment of obesity and obesity-related metabolic disorders. We examined the effects of Z-551 on obesity and the metabolic disorders in wild-type mice on the high-fat diet (HFD). In mice on the HFD, Z-551 significantly suppressed body weight gain and ameliorated insulin resistance and abnormal glucose and lipid metabolisms. Z-551 inhibited visceral fat mass gain and adipocyte hypertrophy, and reduced molecules involved in fatty acid uptake and synthesis, macrophage infiltration, and inflammation in adipose tissue. Z-551 increased molecules involved in fatty acid combustion, while reduced molecules associated with gluconeogenesis in the liver. Furthermore, Z-551 significantly reduced fasting plasma levels of glucose, triglyceride, free fatty acid, insulin, and leptin. To elucidate the significance of the PPAR combination, we examined the effects of Z-551 in PPARα-deficient mice and those of a synthetic PPARγ antagonist in wild-type mice on the HFD. Both drugs showed similar, but weaker effects on body weight, insulin resistance and specific events provoked in adipose tissue compared with those of Z-551 as described above, except for lack of effects on fasting plasma triglyceride and free fatty acid levels. These findings suggest that Z-551 ameliorates HFD-induced obesity, insulin resistance, and impairment of glucose and lipid metabolisms by PPARα agonistic and PPARγ antagonistic activities, and therefore, might be clinically useful for preventing or treating obesity and obesity-related metabolic disorders such as insulin resistance, type 2 diabetes, and dyslipidemia.

  1. High-fat diet-induced reduction of peroxisome proliferator-activated receptor-γ coactivator-1α messenger RNA levels and oxidative capacity in the soleus muscle of rats with metabolic syndrome.

    PubMed

    Nagatomo, Fumiko; Fujino, Hidemi; Kondo, Hiroyo; Takeda, Isao; Tsuda, Kinsuke; Ishihara, Akihiko

    2012-02-01

    Animal models of type 2 diabetes exhibit reduced peroxisome proliferator-activated receptor-γ coactivator-1α (PGC-1α) messenger RNA (mRNA) levels, which are associated with decreased oxidative capacity, in skeletal muscles. In contrast, animal models with metabolic syndrome show normal PGC-1α mRNA levels. We hypothesized that a high-fat diet decreases PGC-1α mRNA levels in skeletal muscles of rats with metabolic syndrome, reducing muscle oxidative capacity and accelerating metabolic syndrome or inducing type 2 diabetes. We examined mRNA levels and fiber profiles in the soleus muscles of rats with metabolic syndrome (SHR/NDmcr-cp [cp/cp]; CP) fed a high-fat diet. Five-week-old CP rats were assigned to a sedentary group (CP-N) that was fed a standard diet (15.1 kJ/g, 23.6% protein, 5.3% fat, and 54.4% carbohydrates) or a sedentary group (CP-H) that was fed a high-fat diet (21.6 kJ/g, 23.6% protein, 34.9% fat, and 25.9% carbohydrates) and were housed for 10 weeks. Body weight, energy intake, and systolic blood pressure were higher in the CP-H group than in the CP-N group. Nonfasting glucose, triglyceride, total cholesterol, and leptin levels were higher in the CP-H group than in the CP-N group. There was no difference in insulin levels between the CP-N and CP-H groups. Muscle PGC-1α mRNA levels and succinate dehydrogenase activity were lower in the CP-H group than in the CP-N group. We concluded that a high-fat diet reduces PGC-1α mRNA levels and oxidative capacity in skeletal muscles and accelerates metabolic syndrome.

  2. Grape seed proanthocyanidin extracts ameliorate podocyte injury by activating peroxisome proliferator-activated receptor-γ coactivator 1α in low-dose streptozotocin-and high-carbohydrate/high-fat diet-induced diabetic rats.

    PubMed

    Bao, Lei; Cai, Xiaxia; Dai, Xiaoqian; Ding, Ye; Jiang, Yanfei; Li, Yujie; Zhang, Zhaofeng; Li, Yong

    2014-08-01

    Podocytes are part of the glomerular filtration membrane in kidney and serve to prevent the filtration of protein from the blood. Several evidences suggest that mitochondrial dysfunction plays a critical role in the pathogenesis of diabetic nephropathy and it is an early event in podocyte injury. Mitochondrial dysfunction promotes oxidative stress that can favor the development of podocyte injury. Peroxisome proliferator-activated receptor-γ coactivator 1α (PGC-1α) was considered to be a major regulator of metabolic homeostasis and mitochondrial function. Some studies indicated that polyphenols may improve mitochondrial dysfunction, maintain the podocyte integrity and have therapeutic effects on glomerular diseases by promoting PGC-1α expression. Our study investigated whether grape seed proanthocyanidin extracts (GSPE), a strong antioxidant, ameliorate podocyte injury by activating PGC-1α in low-dose streptozotocin-and high-carbohydrate/high-fat diet-induced diabetic rats. After 16 weeks of GSPE treatment, GSPE slightly increased the body weight and decreased plasma glucose, food intake, water intake and urine volume in diabetic rats. Further, GSPE significantly decreased 24 h albumin levels and increased the expression of nephrin and podocalyxin. The antioxidant levels were improved and the cellular damage of kidney in diabetic rats was also relieved effectively after the treatment. Moreover, GSPE increased the mRNA expression of mitochondrial biogenesis factors and mitochondrial DNA content. Finally, GSPE activated the expression of PGC-1α, silent mating type information regulation 2 homolog 1 (SIRT1) and AMP-activated protein kinase (AMPK). These results suggest that GSPE ameliorate podocyte injury in diabetic nephropathy by the activation of AMPK-SIRT1-PGC-1α signalling, which appears to inhibit oxidative stress and mitochondrial dysfunction in the kidney.

  3. Calpain Inhibitor PD150606 Attenuates Glutamate Induced Spiral Ganglion Neuron Apoptosis through Apoptosis Inducing Factor Pathway In Vitro

    PubMed Central

    Song, Yong-Li; Chen, Xiao-Dong; Mi, Wen-Juan; Wang, Jian; Lin, Ying; Chen, Fu-Quan; Qiu, Jian-Hua

    2015-01-01

    Objective This research aimed to investigate whether glutamate induced spiral ganglion neurons (SGNs) apoptosis through apoptosis inducing factor (AIF) pathway. And verify whether PD150606, a calpain inhibitor could prevent apoptosis by inhibiting cleaving and releasing AIF in mitochondrion. Methods SGNs of postnatal days 0-3 were harvested and cultured in dishes. 20 mM Glu, the caspase inhibitor Z-VAD-FMK and calpain inhibitor PD150606 were added into cultured dishes separately. We used optical microscope and immunofluoresence staining to observe cell morphology and AIF distribution, RT-PCR and Westernblot to analyse AIF and calpain expression in SGNs. TUNEL assay was used to test cell apoptosis. Results Cell morphology and nuclear translocation of AIF were altered in SGNs by 20 mM Glu treated in vitro. The axon of SGN shortened, more apoptosis SGN were observed and the expression of AIF and calpain were up-regulated in Glu-treated group than the normal one (P<0.05). The same experiments were conducted in 20 mM+PD150606 treated group and 20 mM+Z-VAD-FMK group. Obviously AIF were located from cytoplasm to the nuclear and the expressions of AIF and calpain were down-regulated by PD150606 (P<0.05). Positive cells in TUNEL staining decreased after PD150606 treating. However, Z-VAD-FMK had no influence on AIF, calpain expression or cell apoptosis. Conclusion The AIF-related apoptosis pathway is involved in the process of Glu-induced SGN injury. Furthermore, the inhibition of calpain can prevent AIF from releasing the nuclear or inducing SGN apoptosis. PMID:25874633

  4. Comparative Study of Proton Pump Inhibitors on Dexamethasone Plus Pylorus Ligation Induced Ulcer Model in Rats

    PubMed Central

    Thippeswamy, A. H. M.; Sajjan, M.; Palkar, M. B.; Koti, B. C.; Viswanathaswamy, A. H. M.

    2010-01-01

    The present study was designed to compare ulcer protective effect of proton pump inhibitors viz. omeprazole, rabeprazole and lansoprazole against dexamethasone plus pylorus ligation induced ulcer model. Dexamethasone (5 mg/kg) was used as an ulcerogen. Dexamethasone suspended in 1% CMC in water was given orally to all the rats 15 min after the pylorus ligation. Omeprazole (20 mg/kg), rabeprazole (20 mg/kg), and lansoprazole (20 mg/kg) were administered by oral route 30 min prior to ligation was used for ulcer protective studies, gastric secretion and mucosal studies. Effects of proton pump inhibitors were determined by the evaluation of various biochemical parameters such as ulcer index, free and total acidity, gastric pH, mucin, pepsin and total proteins. Oral administration of proton pump inhibitors showed significant reduction in gastric acid secretion and ulcer protective activity against dexamethasone plus pylorus ligation induced ulcer model. The % protection of omeprazole, rabeprazole and lansoprazole was 84.04, 89.36 and 79.78, respectively. Rabeprazole significantly inhibited the acid-pepsin secretion and increased the gastric mucin secretion. The observations made in the present study suggest that rabeprazole is the most effective gastric antisecretory and ulcer healing agent as compared to omeprazole and lansoprazole. PMID:21188049

  5. Bromophenacyl bromide, a phospholipase A2 inhibitor attenuates chemically induced gastroduodenal ulcers in rats

    PubMed Central

    Tariq, Mohammad; Elfaki, Ibrahim; Khan, Haseeb Ahmad; Arshaduddin, Mohammad; Sobki, Samia; Moutaery, Meshal Al

    2006-01-01

    AIM: To study the effect of bromophenacyl bromide (BPB), a phospholipase A2 inhibitor on gastric secretion and to protect chemically induced gastric and duodenal ulcers in rats. METHODS: Acid secretion studies were undertaken in pylorus-ligated rats with BPB treatment (0, 5, 15 and 45 mg/kg). Gastric and duodenal lesions in the rats were induced by ethanol and cysteamine respectively. The levels of gastric wall mucus, nonprotein sulfhydryls (NP-SH) and myeloperoxidase (MPO) were also measured in the glandular stomach of rats following ethanol induced gastric lesions. RESULTS: BPB produced a dose-dependent inhibition of gastric acid secretion and acidity in rats. Pretreatment with BPB significantly attenuated the formation of ethanol induced gastric lesion. BPB also protected intestinal mucosa against cysteamine-induced duodenal ulcers. The antiulcer activity of BPB was associated with significant inhibition of ethanol-induced depletion of gastric wall mucus, NP-SH and MPO. These findings pointed towards the mediation of sulfhydryls in BPB induced gastrointestinal cytoprotection. CONCLUSION: BPB possesses significant antiulcer and cytoprotective activity against experimentally induced gastroduodenal lesions. PMID:17007045

  6. CTA095, a novel Etk and Src dual inhibitor, induces apoptosis in prostate cancer cells and overcomes resistance to Src inhibitors.

    PubMed

    Guo, Wenchang; Liu, Ruiwu; Bhardwaj, Gaurav; Ma, Ai-Hong; Changou, Chun; Yang, Joy C; Li, Yuanpei; Feng, Caihong; Luo, Yan; Mazloom, Anisha; Sanchez, Eduardo; Wang, Yan; Huang, Wenzhe; Patterson, Randen; Evans, Christopher P; Lam, Kit S; Kung, Hsing-Jien

    2013-01-01

    Etk is a non-receptor tyrosine kinase, which provides a strong survival signal in human prostate cancer cells. Src, another tyrosine kinase that cross-activates with Etk, has been shown to play an important role in prostate cancer metastasis. Herein, we discovered a new class of Etk inhibitors. Within those inhibitors, CTA095 was identified as a potent Etk and Src dual inhibitor. CTA095 was found to induce autophagy as well as apoptosis in human prostate cancer cells. In addition, CTA095 inhibited HUVEC cell tube formation and "wound healing" of human prostate cancer cells, implying its role in inhibition of angiogenesis and metastasis of human prostate cancer. More interestingly, CTA095 could overcome Src inhibitor resistance in prostate cancer cells. It induces apoptosis in Src inhibitor resistant prostate cancer cells, likely through a mechanism of down regulation of Myc and BCL2. This finding indicates that simultaneously targeting Etk and Src could be a promising approach to overcome drug resistance in prostate cancer. PMID:23967135

  7. CTA095, a Novel Etk and Src Dual Inhibitor, Induces Apoptosis in Prostate Cancer Cells and Overcomes Resistance to Src Inhibitors

    PubMed Central

    Guo, Wenchang; Liu, Ruiwu; Bhardwaj, Gaurav; Ma, Ai-Hong; Changou, Chun; Yang, Joy C.; Li, Yuanpei; Feng, Caihong; Luo, Yan; Mazloom, Anisha; Sanchez, Eduardo; Wang, Yan; Huang, Wenzhe; Patterson, Randen; Evans, Christopher P.; Lam, Kit S.; Kung, Hsing-Jien

    2013-01-01

    Etk is a non-receptor tyrosine kinase, which provides a strong survival signal in human prostate cancer cells. Src, another tyrosine kinase that cross-activates with Etk, has been shown to play an important role in prostate cancer metastasis. Herein, we discovered a new class of Etk inhibitors. Within those inhibitors, CTA095 was identified as a potent Etk and Src dual inhibitor. CTA095 was found to induce autophagy as well as apoptosis in human prostate cancer cells. In addition, CTA095 inhibited HUVEC cell tube formation and “wound healing” of human prostate cancer cells, implying its role in inhibition of angiogenesis and metastasis of human prostate cancer. More interestingly, CTA095 could overcome Src inhibitor resistance in prostate cancer cells. It induces apoptosis in Src inhibitor resistant prostate cancer cells, likely through a mechanism of down regulation of Myc and BCL2. This finding indicates that simultaneously targeting Etk and Src could be a promising approach to overcome drug resistance in prostate cancer. PMID:23967135

  8. Diverse intracellular pathogens activate type III interferon expression from peroxisomes.

    PubMed

    Odendall, Charlotte; Dixit, Evelyn; Stavru, Fabrizia; Bierne, Helene; Franz, Kate M; Durbin, Ann Fiegen; Boulant, Steeve; Gehrke, Lee; Cossart, Pascale; Kagan, Jonathan C

    2014-08-01

    Type I interferon responses are considered the primary means by which viral infections are controlled in mammals. Despite this view, several pathogens activate antiviral responses in the absence of type I interferons. The mechanisms controlling type I interferon-independent responses are undefined. We found that RIG-I like receptors (RLRs) induce type III interferon expression in a variety of human cell types, and identified factors that differentially regulate expression of type I and type III interferons. We identified peroxisomes as a primary site of initiation of type III interferon expression, and revealed that the process of intestinal epithelial cell differentiation upregulates peroxisome biogenesis and promotes robust type III interferon responses in human cells. These findings highlight the importance of different intracellular organelles in specific innate immune responses.

  9. Diverse intracellular pathogens activate Type III Interferon expression from peroxisomes

    PubMed Central

    Odendall, Charlotte; Dixit, Evelyn; Stavru, Fabrizia; Bierne, Helene; Franz, Kate M.; Fiegen, Ann; Boulant, Steeve; Gehrke, Lee; Cossart, Pascale; Kagan, Jonathan C.

    2014-01-01

    Type I Interferon (IFN) responses are considered the primary means by which viral infections are controlled in mammals. Despite this view, several pathogens activate antiviral responses in the absence of Type I IFNs. The mechanisms controlling Type I IFN-independent responses are undefined. We have found that RIG-I like Receptors (RLRs) induce Type III IFN expression in a variety of human cell types, and identified factors that differentially regulate Type I and III IFN expression. We identified peroxisomes as a primary site that initiates Type III IFN expression, and revealed that the process of intestinal epithelial cell differentiation upregulates peroxisome biogenesis and promotes robust Type III IFN responses in human cells. These findings highlight the interconnections between innate immunity and cell biology. PMID:24952503

  10. Effects of Lorenzo's Oil on peroxisomes in healthy mice.

    PubMed

    De Craemer, D; Van den Branden, C; Fontaine, M; Vamecq, J

    1998-03-01

    We investigated peroxisomal alterations in mice treated with different doses of Lorenzo's Oil (a therapy for X-linked adrenoleukodystrophy patients) for up to 100 days. Hepatic erucic acid levels were already significantly increased 2.2-fold and 2.6-fold in mice treated with 10% and 20% Lorenzo's Oil for 21 days, respectively. No lipidosis was found in liver, myocardium and kidney of any of the treated mice. While hepatic catalase, lauroyl-CoA oxidase and glycolate oxidase, and renal catalase activities were not induced by either diet, myocardial catalase activity was increased in most groups. This suggests that the mechanism of the effect of Lorenzo's Oil in X-linked adrenoleukodystrophy patients may not be a direct effect on the peroxisomes.

  11. Interferon-α and cyclooxygenase-2 inhibitor cooperatively mediates TRAIL-induced apoptosis in hepatocellular carcinoma

    SciTech Connect

    Zuo, Chaohui; Qiu, Xiaoxin; Liu, Nianli; Yang, Darong; Xia, Man; Liu, Jingshi; Wang, Xiaohong; and others

    2015-05-01

    Hepatocellular carcinoma (HCC) is a leading cause of cancer-related mortality worldwide. Interferon-alpha (IFN-α) has recently been recognized to harbor therapeutic potential in the prevention and treatment of HCC, but it remains controversial as to whether IFN-α exerts direct cytotoxicity against HCC. Cyclooxygenase-2 (COX-2) is overexpressed in HCC and is considered to play a role in hepatocarcinogenesis. Therefore, we aimed to elucidate the combined effect of a COX-2 inhibitor, celecoxib, and IFN-α on in vitro growth suppression of HCC using the hepatoma cell line HLCZ01 and the in vivo nude mouse xenotransplantation model using HLCZ01 cells. Treatment with celecoxib and IFN-α synergistically inhibited cell proliferation in a dose- and time-dependent manner. Apoptosis was identified by 4',6-diamidino-2-phenylindole dihydrochloride and fluorescent staining. IFN-α upregulated the expression of TRAIL, while celecoxib increased the expression of TRAIL receptors. The combined regimen with celecoxib and IFN-α reduced the growth of xenotransplanted HCCs in nude mice. The regulation of IFN-α- and COX-2 inhibitor-induced cell death is impaired in a subset of TRAIL-resistant cells. The molecular mechanisms of HCC cells resistant to TRAIL-induced apoptosis were explored using molecular biological and immunological methods. Interferon-α and the COX-2 inhibitor celecoxib synergistically increased TRAIL-induced apoptosis in hepatocellular carcinoma. These data suggest that IFN-α and celecoxib may offer a novel role with important implications in designing new therapeutics for TRAIL-resistant tumors. - Highlights: ●The cytotoxic effect of TRAIL on a developed HCC HLCZ01 cells infected with HBV. ●IFN-α and celecoxib induced apoptosis in HLCZ01 cells infected with HBV. ●The combined regime reduced the growth of xenotransplanted HCCs in nude mice model.

  12. Suppression of VEGF-induced angiogenesis by the protein tyrosine kinase inhibitor, lavendustin A.

    PubMed Central

    Hu, D E; Fan, T P

    1995-01-01

    1. Vascular endothelial growth factor (VEGF) is a heparin-binding angiogenic factor which specifically acts on endothelial cells via distinct membrane-spanning tyrosine kinase receptors. Here we used the rat sponge implant model to test the hypothesis that the angiogenic activity of VEGF can be suppressed by protein tyrosine kinase (PTK) inhibitors. 2. Neovascular responses in subcutaneous sponge implants were determined by measurements of relative sponge blood flow by use of a 133Xe clearance technique, and confirmed by histological studies and morphometric analysis. 3. Daily local administration of 250 ng VEGF165 accelerated the rate of 133Xe clearance from the sponges and induced an intense neovascularisation. This VEGF165-induced angiogenesis was inhibited by daily co-administration of the selective PTK inhibitor, lavendustin A (10 micrograms), but not its negative control, lavendustin B (10 micrograms). Blood flow measurements and morphometric analysis of 8-day-old sponges showed that lavendustin A reduced the 133Xe clearance of VEGF165-treated sponges from 32.9 +/- 1.5% to 20.9 +/- 1.6% and the total fibrovascular growth area from 62.4 +/- 6.1% to 21.6 +/- 6.8% (n = 12, P < 0.05). 4. Co-injection of suramin (3 mg), an inhibitor of heparin-binding growth factors, also suppressed the VEGF165-elicited neovascular response. In contrast, neither lavendustin A nor suramin produced any effect on the basal sponge-induced angiogenesis. 5. When given alone, low doses of VEGF165 (25 ng) or basic fibroblast growth factor (bFGF; 10 ng) did not modify the basal sponge-induced neovascularisation.(ABSTRACT TRUNCATED AT 250 WORDS) Images Figure 2 Figure 2 PMID:7533611

  13. Hybrid inhibitor of peripheral cannabinoid-1 receptors and inducible nitric oxide synthase mitigates liver fibrosis

    PubMed Central

    Iyer, Malliga R.; Liu, Ziyi; Cao, Zongxian; Jourdan, Tony; Erdelyi, Katalin; Godlewski, Grzegorz; Szanda, Gergő; Liu, Jie; Park, Joshua K.; Mukhopadhyay, Bani; Rosenberg, Avi Z.; Liow, Jeih-San; Lorenz, Robin G.; Pacher, Pal; Innis, Robert B.

    2016-01-01

    Liver fibrosis, a consequence of chronic liver injury and a way station to cirrhosis and hepatocellular carcinoma, lacks effective treatment. Endocannabinoids acting via cannabinoid-1 receptors (CB1R) induce profibrotic gene expression and promote pathologies that predispose to liver fibrosis. CB1R antagonists produce opposite effects, but their therapeutic development was halted due to neuropsychiatric side effects. Inducible nitric oxide synthase (iNOS) also promotes liver fibrosis and its underlying pathologies, but iNOS inhibitors tested to date showed limited therapeutic efficacy in inflammatory diseases. Here, we introduce a peripherally restricted, orally bioavailable CB1R antagonist, which accumulates in liver to release an iNOS inhibitory leaving group. In mouse models of fibrosis induced by CCl4 or bile duct ligation, the hybrid CB1R/iNOS antagonist surpassed the antifibrotic efficacy of the CB1R antagonist rimonabant or the iNOS inhibitor 1400W, without inducing anxiety-like behaviors or CB1R occupancy in the CNS. The hybrid inhibitor also targeted CB1R-independent, iNOS-mediated profibrotic pathways, including increased PDGF, Nlrp3/Asc3, and integrin αvβ6 signaling, as judged by its ability to inhibit these pathways in cnr1–/– but not in nos2–/– mice. Additionally, it was able to slow fibrosis progression and to attenuate established fibrosis. Thus, dual-target peripheral CB1R/iNOS antagonists have therapeutic potential in liver fibrosis. PMID:27525312

  14. Hybrid inhibitor of peripheral cannabinoid-1 receptors and inducible nitric oxide synthase mitigates liver fibrosis

    PubMed Central

    Liu, Ziyi; Cao, Zongxian; Jourdan, Tony; Erdelyi, Katalin; Godlewski, Grzegorz; Szanda, Gergő; Liu, Jie; Park, Joshua K.; Mukhopadhyay, Bani; Rosenberg, Avi Z.; Liow, Jeih-San; Lorenz, Robin G.; Pacher, Pal; Innis, Robert B.; Kunos, George

    2016-01-01

    Liver fibrosis, a consequence of chronic liver injury and a way station to cirrhosis and hepatocellular carcinoma, lacks effective treatment. Endocannabinoids acting via cannabinoid-1 receptors (CB1R) induce profibrotic gene expression and promote pathologies that predispose to liver fibrosis. CB1R antagonists produce opposite effects, but their therapeutic development was halted due to neuropsychiatric side effects. Inducible nitric oxide synthase (iNOS) also promotes liver fibrosis and its underlying pathologies, but iNOS inhibitors tested to date showed limited therapeutic efficacy in inflammatory diseases. Here, we introduce a peripherally restricted, orally bioavailable CB1R antagonist, which accumulates in liver to release an iNOS inhibitory leaving group. In mouse models of fibrosis induced by CCl4 or bile duct ligation, the hybrid CB1R/iNOS antagonist surpassed the antifibrotic efficacy of the CB1R antagonist rimonabant or the iNOS inhibitor 1400W, without inducing anxiety-like behaviors or CB1R occupancy in the CNS. The hybrid inhibitor also targeted CB1R-independent, iNOS-mediated profibrotic pathways, including increased PDGF, Nlrp3/Asc3, and integrin αvβ6 signaling, as judged by its ability to inhibit these pathways in cnr1−/− but not in nos2−/− mice. Additionally, it was able to slow fibrosis progression and to attenuate established fibrosis. Thus, dual-target peripheral CB1R/iNOS antagonists have therapeutic potential in liver fibrosis. PMID:27525312

  15. Nuclear factor kappaB inhibitors induce adhesion-dependent colon cancer apoptosis: implications for metastasis.

    PubMed

    Scaife, Courtney L; Kuang, Jinqiu; Wills, Jason C; Trowbridge, D Brad; Gray, Phil; Manning, Bernadette M; Eichwald, Ernst J; Daynes, Raymond A; Kuwada, Scott K

    2002-12-01

    The transcription factor nuclear factor kappaB (NFkappaB) is constitutively active in many types of cancercells and regulates the expression of several antiapoptotic genes. Previous studies demonstrated a role for the inhibition of NFkappaB in cancer therapyusing a transgenic approach in mice. We found that NFkappaB was transiently activated much greater than background constitutive levels during colon cancer cell readhesion, which rendered the readhering colon cancer cells exquisitely susceptible to apoptosis in the presence of soluble NFkappaB inhibitors. These compounds greatly reduced colon cancer cell implantation in an in vivo seeding model of metastasis. The ability of soluble NFkappaB inhibitors to significantly induce apoptosis of readherent colon cancer cells makes them prospective candidates for preventing colon cancer metastasis.

  16. Hypoxia inducible factor 1α expression and effects of its inhibitors in canine lymphoma

    PubMed Central

    KAMBAYASHI, Satoshi; IGASE, Masaya; KOBAYASHI, Kosuke; KIMURA, Ayana; SHIMOKAWA MIYAMA, Takako; BABA, Kenji; NOGUCHI, Shunsuke; MIZUNO, Takuya; OKUDA, Masaru

    2015-01-01

    Hypoxic conditions in various cancers are believed to relate with their malignancy, and hypoxia inducible factor-1α (HIF-1α) has been shown to be a major regulator of the response to low oxygen. In this study, we examined HIF-1α expression in canine lymphoma using cell lines and clinical samples and found that these cells expressed HIF-1α. Moreover, the HIF-1α inhibitors, echinomycin, YC-1 and 2-methoxyestradiol, suppressed the proliferation of canine lymphoma cell lines. In a xenograft model using NOD/scid mice, echinomycin treatment resulted in a dose-dependent regression of the tumor. Our results suggest that HIF-1α contributes to the proliferation and/or survival of canine lymphoma cells. Therefore, HIF-1α inhibitors may be potential agents to treat canine lymphoma. PMID:26050843

  17. Valproic acid defines a novel class of HDAC inhibitors inducing differentiation of transformed cells.

    PubMed

    Göttlicher, M; Minucci, S; Zhu, P; Krämer, O H; Schimpf, A; Giavara, S; Sleeman, J P; Lo Coco, F; Nervi, C; Pelicci, P G; Heinzel, T

    2001-12-17

    Histone deacetylases (HDACs) play important roles in transcriptional regulation and pathogenesis of cancer. Thus, HDAC inhibitors are candidate drugs for differentiation therapy of cancer. Here, we show that the well-tolerated antiepileptic drug valproic acid is a powerful HDAC inhibitor. Valproic acid relieves HDAC-dependent transcriptional repression and causes hyperacetylation of histones in cultured cells and in vivo. Valproic acid inhibits HDAC activity in vitro, most probably by binding to the catalytic center of HDACs. Most importantly, valproic acid induces differentiation of carcinoma cells, transformed hematopoietic progenitor cells and leukemic blasts from acute myeloid leukemia patients. More over, tumor growth and metastasis formation are significantly reduced in animal experiments. Therefore, valproic acid might serve as an effective drug for cancer therapy. PMID:11742974

  18. Valproic acid defines a novel class of HDAC inhibitors inducing differentiation of transformed cells

    PubMed Central

    Göttlicher, Martin; Minucci, Saverio; Zhu, Ping; Krämer, Oliver H.; Schimpf, Annemarie; Giavara, Sabrina; Sleeman, Jonathan P.; Lo Coco, Francesco; Nervi, Clara; Pelicci, Pier Giuseppe; Heinzel, Thorsten

    2001-01-01

    Histone deacetylases (HDACs) play important roles in transcriptional regulation and pathogenesis of cancer. Thus, HDAC inhibitors are candidate drugs for differentiation therapy of cancer. Here, we show that the well-tolerated antiepileptic drug valproic acid is a powerful HDAC inhibitor. Valproic acid relieves HDAC-dependent transcriptional repression and causes hyperacetylation of histones in cultured cells and in vivo. Valproic acid inhibits HDAC activity in vitro, most probably by binding to the catalytic center of HDACs. Most importantly, valproic acid induces differentiation of carcinoma cells, transformed hematopoietic progenitor cells and leukemic blasts from acute myeloid leukemia patients. More over, tumor growth and metastasis formation are significantly reduced in animal experiments. Therefore, valproic acid might serve as an effective drug for cancer therapy. PMID:11742974

  19. A dual inhibitor of cyclooxygenase and 5-lipoxygenase protects against kainic acid-induced brain injury.

    PubMed

    Minutoli, Letteria; Marini, Herbert; Rinaldi, Mariagrazia; Bitto, Alessandra; Irrera, Natasha; Pizzino, Gabriele; Pallio, Giovanni; Calò, Margherita; Adamo, Elena Bianca; Trichilo, Vincenzo; Interdonato, Monica; Galfo, Federica; Squadrito, Francesco; Altavilla, Domenica

    2015-06-01

    Systemic administration of kainic acid causes inflammation and apoptosis in the brain, resulting in neuronal loss. Dual cyclooxygenase/5-lipoxygenase (COX/5-LOX) inhibitors could represent a possible neuroprotective approach in preventing glutamate excitotoxicity. Consequently, we investigated the effects of a dual inhibitor of COX/5-LOX following intraperitoneal administration of kainic acid (KA, 10 mg/kg) in rats. Animals were randomized to receive either the dual inhibitor of COX/5-LOX (flavocoxid, 20 mg/kg i.p.) or its vehicle (1 ml/kg i.p.) 30 min after KA administration. Sham brain injury rats were used as controls. We evaluated protein expression of phosphorylated extracellular signal-regulated kinase (p-ERK1/2) and tumor necrosis factor alpha (TNF-α) as well as levels of malondialdehyde (MDA), prostaglandin E2 (PGE2) and leukotriene B4 (LTB4) in the hippocampus. Animals were also observed for monitoring behavioral changes according to Racine Scale. Finally, histological analysis and brain edema evaluation were carried out. Treatment with the dual inhibitor of COX/5-LOX decreased protein expression of p-ERK1/2 and TNF-α in hippocampus, markedly reduced MDA, LTB4 and PGE2 hippocampal levels, and also ameliorated brain edema. Histological analysis showed a reduction in cell damage in rats treated with the dual inhibitor of COX/5-LOX, particularly in hippocampal subregion CA3c. Moreover, flavocoxid significantly improved behavioral signs following kainic acid administration. Our results suggest that dual inhibition of COX/5-LOX by flavocoxid has neuroprotective effects during kainic acid-induced excitotoxicity. PMID:25893744

  20. Targeting and insertion of peroxisomal membrane proteins: ER trafficking versus direct delivery to peroxisomes.

    PubMed

    Mayerhofer, Peter U

    2016-05-01

    The importance of peroxisomes is highlighted by severe inherited human disorders linked to impaired peroxisomal biogenesis. Besides the simple architecture of these ubiquitous and dynamic organelles, their biogenesis is surprisingly complex and involves specialized proteins, termed peroxins, which mediate targeting and insertion of peroxisomal membrane proteins (PMPs) into the peroxisomal bilayer, and the import of soluble proteins into the protein-dense matrix of the organelle. The long-standing paradigm that all peroxisomal proteins are imported directly into preexisting peroxisomes has been challenged by the detection of PMPs inside the endoplasmic reticulum (ER). New models propose that the ER originates peroxisomal biogenesis by mediating PMP trafficking to the peroxisomes via budding vesicles. However, the relative contribution of this ER-derived pathway to the total peroxisome population in vivo, and the detailed mechanisms of ER entry and exit of PMPs are controversially discussed. This review aims to summarize present knowledge about how PMPs are targeted to the ER, instead of being inserted directly into preexisting peroxisomes. Moreover, molecular mechanisms that facilitate bilayer insertion of PMPs among different species are discussed.

  1. Factors Affecting Development of Peroxisomes and Glycolate Metabolism among Algae of Different Evolutionary Lines of the Prasinophyceae.

    PubMed

    Kehlenbeck, P.; Goyal, A.; Tolbert, N. E.

    1995-12-01

    Leaf-type peroxisomes are not present in the primitive unicellular Prasinophycean line of algae but are present in the multicellular algae Mougeotia, Chara, and Nitella, which are in the one evolutionary line, Charophyceae, that led to higher plants. Processes related to glycolate metabolism that may have been modified or induced with the appearance of peroxisomes have been examined. The algal dissolved inorganic carbon-concentrating mechanism and alkalization of the medium during photosynthesis were not lost when peroxisomes appeared in the members of the Charophycean line of algae. Therefore, it is unlikely that lowering of the CO2 concentration in the environment was a major factor in the evolutionary appearance of peroxisomes. Multicellular Mougeotia, early members of the Charophycean line of algae, have peroxisomes, but they excrete excess glycolate into the medium. The cytosolic pyruvate reductase for D-lactate synthesis and the glycolate dehydrogenase activity almost disappeared when peroxisomal glycolate oxidase, which also oxidizes L-lactate, appeared. These biochemical changes do not indicate what caused the induction of leaf-type peroxisomes in this evolutionary line of algae. The oxygenase activity of ribulose-1,5-bisphosphate carboxylase/oxygenase and glycolate oxidase require about 200 to 400 [mu]M O2 for 0.5 Vmax. These high-O2-requiring steps in glycolate metabolism would have functioned faster with increasing atmospheric O2, which might have been the causative factor in the induction of peroxisomes.

  2. Age-dependent roles of peroxisomes in the hippocampus of a transgenic mouse model of Alzheimer’s disease

    PubMed Central

    2013-01-01

    Background Alzheimer’s Disease (AD) is a progressive neurodegenerative disease, especially affecting the hippocampus. Impairment of cognitive and memory functions is associated with amyloid β-peptide-induced oxidative stress and alterations in lipid metabolism. In this scenario, the dual role of peroxisomes in producing and removing ROS, and their function in fatty acids β-oxidation, may be critical. This work aims to investigating the possible involvement of peroxisomes in AD onset and progression, as studied in a transgenic mouse model, harboring the human Swedish familial AD mutation. We therefore characterized the peroxisomal population in the hippocampus, focusing on early, advanced, and late stages of the disease (3, 6, 9, 12, 18 months of age). Several peroxisome-related markers in transgenic and wild-type hippocampal formation were comparatively studied, by a combined molecular/immunohistochemical/ultrastructural approach. Results Our results demonstrate early and significant peroxisomal modifications in AD mice, compared to wild-type. Indeed, the peroxisomal membrane protein of 70 kDa and acyl-CoA oxidase 1 are induced at 3 months, possibly reflecting the need for efficient fatty acid β-oxidation, as a compensatory response to mitochondrial dysfunction. The concomitant presence of oxidative damage markers and the altered expression of antioxidant enzymes argue for early oxidative stress in AD. During physiological and pathological brain aging, important changes in the expression of peroxisome-related proteins, also correlating with ongoing gliosis, occur in the hippocampus. These age- and genotype-based alterations, strongly dependent on the specific marker considered, indicate metabolic and/or numerical remodeling of peroxisomal population. Conclusions Overall, our data support functional and biogenetic relationships linking peroxisomes to mitochondria and suggest peroxisomal proteins as biomarkers/therapeutic targets in pre-symptomatic AD. PMID

  3. p53 modulates the AMPK inhibitor compound C induced apoptosis in human skin cancer cells

    SciTech Connect

    Huang, Shi-Wei; Wu, Chun-Ying; Wang, Yen-Ting; Kao, Jun-Kai; Lin, Chi-Chen; Chang, Chia-Che; Mu, Szu-Wei; Chen, Yu-Yu; Chiu, Husan-Wen; Chang, Chuan-Hsun; Liang, Shu-Mei; Chen, Yi-Ju; Huang, Jau-Ling; Shieh, Jeng-Jer

    2013-02-15

    Compound C, a well-known inhibitor of the intracellular energy sensor AMP-activated protein kinase (AMPK), has been reported to cause apoptotic cell death in myeloma, breast cancer cells and glioma cells. In this study, we have demonstrated that compound C not only induced autophagy in all tested skin cancer cell lines but also caused more apoptosis in p53 wildtype skin cancer cells than in p53-mutant skin cancer cells. Compound C can induce upregulation, phosphorylation and nuclear translocalization of the p53 protein and upregulate expression of p53 target genes in wildtype p53-expressing skin basal cell carcinoma (BCC) cells. The changes of p53 status were dependent on DNA damage which was caused by compound C induced reactive oxygen species (ROS) generation and associated with activated ataxia-telangiectasia mutated (ATM) protein. Using the wildtype p53-expressing BCC cells versus stable p53-knockdown BCC sublines, we present evidence that p53-knockdown cancer cells were much less sensitive to compound C treatment with significant G2/M cell cycle arrest and attenuated the compound C-induced apoptosis but not autophagy. The compound C induced G2/M arrest in p53-knockdown BCC cells was associated with the sustained inactive Tyr15 phosphor-Cdc2 expression. Overall, our results established that compound C-induced apoptosis in skin cancer cells was dependent on the cell's p53 status. - Highlights: ► Compound C caused more apoptosis in p53 wildtype than p53-mutant skin cancer cells. ► Compound C can upregulate p53 expression and induce p53 activation. ► Compound C induced p53 effects were dependent on ROS induced DNA damage pathway. ► p53-knockdown attenuated compound C-induced apoptosis but not autophagy. ► Compound C-induced apoptosis in skin cancer cells was dependent on p53 status.

  4. Angiotensin II induces secretion of plasminogen activator inhibitor 1 and a tissue metalloprotease inhibitor-related protein from rat brain astrocytes

    SciTech Connect

    Olson, J.A. Jr.; Shiverick, K.T.; Ogilvie, S.; Buhi, W.C.; Raizada, M.K. )

    1991-03-01

    The present study investigates angiotensin (Ang) II effects on secretory protein synthesis in brain astrocytes cultured from neonatal and 21-day-old rats. Ang II-induced changes in the de novo synthesis of (35S)methionine-labeled secretory proteins were visualized using two-dimensional NaDodSO4/PAGE. Astrocytes from 21-day-old rat brain possess specific high-affinity receptors for Ang II. These cells express two Ang II-induced secretory proteins with Mr 55,000 (AISP-55K) and Mr 30,000 (AISP-30K), which were time- and dose-dependent (EC50, 1 nM). (Sar1, Ile8)Ang II (where Sar is sarcosine) inhibited Ang II-induced secretion of AISP-55K but not AISP-30K. N-terminal amino acid sequencing indicates that AISP-55K is identical to rat plasminogen activator inhibitor 1, whereas AISP-30K exhibits 72-81% identity to three closely related proteins: human tissue inhibitor of metalloproteases, a rat phorbol ester-induced protein, and the murine growth-responsive protein 16C8. Immunofluorescent staining with rat plasminogen activator inhibitor 1 antibody was induced in the majority of cells in culture after Ang II treatment of astrocytes from 21-day-old rat brains. Absence of this response to Ang II in astrocytes from neonatal rat brain provides evidence that this action of Ang II on astrocytes is developmentally regulated.

  5. Poly(ADP-ribose) polymerase inhibitor induces accelerated senescence in irradiated breast cancer cells and tumors

    PubMed Central

    Efimova, Elena V.; Mauceri, Helena J.; Golden, Daniel W.; Labay, Edwardine; Bindokas, Vytautas P.; Darga, Thomas E.; Chakraborty, Chaitali; Andrade, Juan Camilo Barreto; Crawley, Clayton; Sutton, Harold G.; Kron, Stephen J.; Weichselbaum, Ralph R.

    2010-01-01

    Persistent DNA double strand breaks (DSBs) may determine the anti-tumor effects of ionizing radiation (IR) by inducing apoptosis, necrosis, mitotic catastrophe or permanent growth arrest. Ionizing radiation (IR) induces rapid modification of megabase chromatin domains surrounding double strand breaks (DSBs) via poly-ADP-ribosylation, phosphorylation, acetylation, and protein assembly. The dynamics of these ionizing radiation-induced foci (IRIF) have been implicated in DNA damage signaling and DNA repair. As an IRIF reporter, we tracked relocalization of GFP fused to a chromatin binding domain of the checkpoint adapter protein 53BP1 after IR of breast cancer cells and tumors. To block DSB repair in breast cancer cells and tumors, we targeted poly(ADP-ribose) polymerase with ABT-888 (veliparib), one of several PARP inhibitors currently in clinical trials. PARP inhibition markedly enhanced IRIF persistence and increased breast cancer cell senescence both in vitro and in vivo, arguing for targeting IRIF resolution as a novel therapeutic strategy. PMID:20610628

  6. Nonhypoxic regulation and role of hypoxia-inducible factor 1 in aromatase inhibitor resistant breast cancer

    PubMed Central

    2014-01-01

    Introduction Although aromatase inhibitors (AIs; for example, letrozole) are highly effective in treating estrogen receptor positive (ER+) breast cancer, a significant percentage of patients either do not respond to AIs or become resistant to them. Previous studies suggest that acquired resistance to AIs involves a switch from dependence on ER signaling to dependence on growth factor-mediated pathways, such as human epidermal growth factor receptor-2 (HER2). However, the role of HER2, and the identity of other relevant factors that may be used as biomarkers or therapeutic targets remain unknown. This study investigated the potential role of transcription factor hypoxia inducible factor 1 (HIF-1) in acquired AI resistance, and its regulation by HER2. Methods In vitro studies using AI (letrozole or exemestane)-resistant and AI-sensitive cells were conducted to investigate the regulation and role of HIF-1 in AI resistance. Western blot and RT-PCR analyses were conducted to compare protein and mRNA expression, respectively, of ERα, HER2, and HIF-1α (inducible HIF-1 subunit) in AI-resistant versus AI-sensitive cells. Similar expression analyses were also done, along with chromatin immunoprecipitation (ChIP), to identify previously known HIF-1 target genes, such as breast cancer resistance protein (BCRP), that may also play a role in AI resistance. Letrozole-resistant cells were treated with inhibitors to HER2, kinase pathways, and ERα to elucidate the regulation of HIF-1 and BCRP. Lastly, cells were treated with inhibitors or inducers of HIF-1α to determine its importance. Results Basal HIF-1α protein and BCRP mRNA and protein are higher in AI-resistant and HER2-transfected cells than in AI-sensitive, HER2- parental cells under nonhypoxic conditions. HIF-1α expression in AI-resistant cells is likely regulated by HER2 activated-phosphatidylinositide-3-kinase/Akt-protein kinase B/mammalian target of rapamycin (PI3K/Akt/mTOR) pathway, as its expression was inhibited

  7. Epigenetic Manipulation of a Filamentous Fungus by the Proteasome-Inhibitor Bortezomib Induces the Production of an Additional Secondary Metabolite

    PubMed Central

    VanderMolen, Karen M.; Darveaux, Blaise A.; Chen, Wei-Lun; Swanson, Steven M.; Pearce, Cedric J.; Oberlies, Nicholas H.

    2014-01-01

    The use of epigenetic modifiers, such as histone deacetylase inhibitors and DNA methyltransferase inhibitors, has been explored increasingly as a technique to induce the production of additional microbial secondary metabolites. The application of such molecules to microbial cultures has been shown to upregulate otherwise suppressed genes, and in several cases has led to the production of new molecular structures. In this study, the proteasome inhibitor bortezomib was used to induce the production of an additional metabolite from a filamentous fungus (Pleosporales). The induced metabolite was previously isolated from a plant, but the configuration was not assigned until now; in addition, an analogue was isolated from a degraded sample, yielding a new compound. Proteasome inhibitors have not previously been used in this application and offer an additional tool for microbial genome mining. PMID:24955237

  8. Peroxisome Biogenesis Disorders: Biological, Clinical and Pathophysiological Perspectives

    ERIC Educational Resources Information Center

    Braverman, Nancy E.; D'Agostino, Maria Daniela; MacLean, Gillian E.

    2013-01-01

    The peroxisome biogenesis disorders (PBD) are a heterogeneous group of autosomal recessive disorders in which peroxisome assembly is impaired, leading to multiple peroxisome enzyme deficiencies, complex developmental sequelae and progressive disabilities. Mammalian peroxisome assembly involves the protein products of 16 "PEX" genes;…

  9. Vascular dysfunction induced by hypochlorite is improved by the selective phosphodiesterase-5-inhibitor vardenafil.

    PubMed

    Radovits, Tamás; Arif, Rawa; Bömicke, Timo; Korkmaz, Sevil; Barnucz, Enikő; Karck, Matthias; Merkely, Béla; Szabó, Gábor

    2013-06-15

    Reactive oxygen species, such as hypochlorite induce oxidative stress, which impairs nitric oxide (NO)-cyclic guanosine monophosphate (cGMP) signalling and leads to vascular dysfunction. It has been proposed, that elevated cGMP-levels may contribute to an effective cytoprotection against oxidative stress. We investigated the effects of vardenafil, a selective inhibitor of the cGMP-degrading phosphodiesterase-5 enzyme on vascular dysfunction induced by hypochlorite. In organ bath experiments for isometric tension, we investigated the endothelium-dependent and endothelium-independent vasorelaxation of isolated rat aortic rings using cumulative concentrations of acetylcholine and sodium nitroprusside (SNP). Vascular dysfunction was induced by exposing rings to hypochlorite (100-400 µM). In the treatment groups, rats were pretreated with vardenafil (30 and 300 µg/kg i.v.). Immunohistochemical analysis was performed for the oxidative stress markers nitrotyrosine, poly(ADP-ribose) and for apoptosis inducing factor (AIF). Exposure to hypochlorite resulted in a marked impairment of acetylcholine-induced endothelium-dependent vasorelaxation of aortic rings. Pretreatment with vardenafil led to improved endothelial function as reflected by the higher maximal vasorelaxation (Rmax) to acetylcholine. Regarding endothelium-independent vasorelaxation, hypochlorite exposure led to a left-shift of SNP concentration-response curves in the vardenafil groups without any alterations of the Rmax. In the hypochlorite groups immunohistochemical analysis showed enhanced poly(ADP-ribose)-formation and nuclear translocation of AIF, which were prevented by vardenafil-pretreatment. Our results support the view that cytoprotective effects of PDE-5-inhibitors on the endothelium may underlie the improved endothelial function, however, a slight sensitisation of vascular smooth muscle to NO was also confirmed. PDE-5-inhibition may represent a potential therapy approach for treating vascular

  10. Chronic activation of peroxisome proliferator-activated receptor-alpha with fenofibrate prevents alterations in cardiac metabolic phenotype without changing the onset of decompensation in pacing-induced heart failure

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Severe heart failure (HF) is characterized by profound alterations in cardiac metabolic phenotype, with down-regulation of the free fatty acid (FFA) oxidative pathway and marked increase in glucose oxidation. We tested whether fenofibrate, a pharmacological agonist of peroxisome proliferator-activat...

  11. The role of peroxisomal fatty acyl-CoA beta-oxidation in bile acid biosynthesis

    SciTech Connect

    Hayashi, H.; Miwa, A. )

    1989-11-01

    The physiological role of the peroxisomal fatty acyl-CoA beta-oxidizing system (FAOS) is not yet established. We speculated that there might be a relationship between peroxisomal degradation of long-chain fatty acids in the liver and the biosynthesis of bile acids. This was investigated using (1-{sup 14}C)butyric acid and (1-{sup 14}C)lignoceric acid as substrates of FAOS in mitochondria and peroxisomes, respectively. The incorporation of ({sup 14}C)lignoceric acid into primary bile acids was approximately four times higher than that of ({sup 14}C)butyric acid (in terms of C-2 units). The pools of these two fatty acids in the liver were exceedingly small. The incorporations of radioactivity into the primary bile acids were strongly inhibited by administration of aminotriazole, which is a specific inhibitor of peroxisomal FAOS in vivo. Aminotriazole inhibited preferentially the formation of cholate, the major primary bile acid, from both ({sup 14}C)lignoceric acid and ({sup 14}C)butyric acid, rather than the formation of chenodeoxycholate. The former inhibition was about 70% and the latter was approximately 40-50%. In view of reports that cholate is biosynthesized from endogenous cholesterol, the above results indicate that peroxisomal FAOS may have an anabolic function, supplying acetyl CoA for bile acid biosynthesis.

  12. Copper-binding compounds as proteasome inhibitors and apoptosis inducers in human cancer.

    PubMed

    Daniel, Kenyon G; Chen, Di; Yan, Bing; Dou, Q Ping

    2007-01-01

    The trace element copper is vital to the healthy functioning of organisms. Copper is used in a multitude of cellular activities including respiration, angiogenesis, and immune responses. Recently, copper has become a focus in medical research ranging from Alzheimer's disease to cancer. Copper modulation has been suggested to be a potential modality for therapy in these diseases. Several copper-binding compounds have been found to spontaneously complex with copper and form active proteasome inhibitors and apoptosis inducers. This review examines compounds in the quinoline and dithiocarbamate families and from the National Cancer Institute (NCI) Diversity Set that bind with copper and act as anticancer agents. In each case, it is shown that these compounds can bind with copper, inhibit the proteasome activity, and induce apoptosis in cancer cells. These activities are absent when copper is not present. Compounds alone, clioquinol and pyrrolidinedithiocarbamate as examples, are shown to have no effects in normal breast cells. Current research suggests that a possible therapeutic modality for cancer may be developed using the difference of high copper load in tumors versus low copper load in normal cells. This strategy would convert tumor cellular copper into a potent, specific proteasome inhibitor and apoptosis inducer. Thus, this approach could pave the way for the development of nontoxic anticancer therapy.

  13. Peroxisome is a reservoir of intracellular calcium.

    PubMed

    Raychaudhury, Bikramjit; Gupta, Shreedhara; Banerjee, Shouvik; Datta, Salil C

    2006-07-01

    We have examined fura 2-loaded purified peroxisomes under confocal microscope to prove that this mammalian organelle is a store of intracellular calcium pool. Presence of calcium channel and vanadate sensitive Ca(2+)-ATPase in the purified peroxisomal membrane has been demonstrated. We have further observed that machineries to maintain calcium pool in this mammalian organelle are impaired during infection caused by Leishmania donovani. Results reveal that peroxisomes have a merit to play a significant role in the metabolism of intracellular calcium. PMID:16713100

  14. Peroxisomal Pex3 activates selective autophagy of peroxisomes via interaction with the pexophagy receptor Atg30.

    PubMed

    Burnett, Sarah F; Farré, Jean-Claude; Nazarko, Taras Y; Subramani, Suresh

    2015-03-27

    Pexophagy is a process that selectively degrades peroxisomes by autophagy. The Pichia pastoris pexophagy receptor Atg30 is recruited to peroxisomes under peroxisome proliferation conditions. During pexophagy, Atg30 undergoes phosphorylation, a prerequisite for its interactions with the autophagy scaffold protein Atg11 and the ubiquitin-like protein Atg8. Atg30 is subsequently shuttled to the vacuole along with the targeted peroxisome for degradation. Here, we defined the binding site for Atg30 on the peroxisomal membrane protein Pex3 and uncovered a role for Pex3 in the activation of Atg30 via phosphorylation and in the recruitment of Atg11 to the receptor protein complex. Pex3 is classically a docking protein for other proteins that affect peroxisome biogenesis, division, and segregation. We conclude that Pex3 has a role beyond simple docking of Atg30 and that its interaction with Atg30 regulates pexophagy in the yeast P. pastoris.

  15. Curcumin Attenuates Beta-Amyloid-Induced Neuroinflammation via Activation of Peroxisome Proliferator-Activated Receptor-Gamma Function in a Rat Model of Alzheimer's Disease.

    PubMed

    Liu, Zun-Jing; Li, Zhong-Hao; Liu, Lei; Tang, Wen-Xiong; Wang, Yu; Dong, Ming-Rui; Xiao, Cheng

    2016-01-01

    Neuroinflammation is known to have a pivotal role in the pathogenesis of Alzheimer's disease (AD), and curcumin has been reported to have therapeutical effects on AD because of its anti-inflammatory effects. Curcumin is not only a potent PPARγ agonist, but also has neuroprotective effects on cerebral ischemic injury. However, whether PPARγ activated by curcumin is responsible for the anti-neuroinflammation and neuroprotection on AD remains unclear, and needs to be further investigated. Here, using both APP/PS1 transgenic mice and beta-amyloid-induced neuroinflammation in mixed neuronal/glial cultures, we showed that curcumin significantly alleviated spatial memory deficits in APP/PS1 mice and promoted cholinergic neuronal function in vivo and in vitro. Curcumin also reduced the activation of microglia and astrocytes, as well as cytokine production and inhibited nuclear factor kappa B (NF-κB) signaling pathway, suggesting the beneficial effects of curcumin on AD are attributable to the suppression of neuroinflammation. Attenuation of these beneficial effects occurred when co-administrated with PPARγ antagonist GW9662 or silence of PPARγ gene expression, indicating that PPARγ might be involved in anti-inflammatory effects. Circular dichroism and co-immunoprecipitation analysis showed that curcumin directly bound to PPARγ and increased the transcriptional activity and protein levels of PPARγ. Taking together, these data suggested that PPARγ might be a potential target of curcumin, acting to alleviate neuroinflammation and improve neuronal function in AD. PMID:27594837

  16. Curcumin Attenuates Beta-Amyloid-Induced Neuroinflammation via Activation of Peroxisome Proliferator-Activated Receptor-Gamma Function in a Rat Model of Alzheimer's Disease

    PubMed Central

    Liu, Zun-Jing; Li, Zhong-Hao; Liu, Lei; Tang, Wen-Xiong; Wang, Yu; Dong, Ming-Rui; Xiao, Cheng

    2016-01-01

    Neuroinflammation is known to have a pivotal role in the pathogenesis of Alzheimer's disease (AD), and curcumin has been reported to have therapeutical effects on AD because of its anti-inflammatory effects. Curcumin is not only a potent PPARγ agonist, but also has neuroprotective effects on cerebral ischemic injury. However, whether PPARγ activated by curcumin is responsible for the anti-neuroinflammation and neuroprotection on AD remains unclear, and needs to be further investigated. Here, using both APP/PS1 transgenic mice and beta-amyloid-induced neuroinflammation in mixed neuronal/glial cultures, we showed that curcumin significantly alleviated spatial memory deficits in APP/PS1 mice and promoted cholinergic neuronal function in vivo and in vitro. Curcumin also reduced the activation of microglia and astrocytes, as well as cytokine production and inhibited nuclear factor kappa B (NF-κB) signaling pathway, suggesting the beneficial effects of curcumin on AD are attributable to the suppression of neuroinflammation. Attenuation of these beneficial effects occurred when co-administrated with PPARγ antagonist GW9662 or silence of PPARγ gene expression, indicating that PPARγ might be involved in anti-inflammatory effects. Circular dichroism and co-immunoprecipitation analysis showed that curcumin directly bound to PPARγ and increased the transcriptional activity and protein levels of PPARγ. Taking together, these data suggested that PPARγ might be a potential target of curcumin, acting to alleviate neuroinflammation and improve neuronal function in AD.

  17. Curcumin Attenuates Beta-Amyloid-Induced Neuroinflammation via Activation of Peroxisome Proliferator-Activated Receptor-Gamma Function in a Rat Model of Alzheimer's Disease

    PubMed Central

    Liu, Zun-Jing; Li, Zhong-Hao; Liu, Lei; Tang, Wen-Xiong; Wang, Yu; Dong, Ming-Rui; Xiao, Cheng

    2016-01-01

    Neuroinflammation is known to have a pivotal role in the pathogenesis of Alzheimer's disease (AD), and curcumin has been reported to have therapeutical effects on AD because of its anti-inflammatory effects. Curcumin is not only a potent PPARγ agonist, but also has neuroprotective effects on cerebral ischemic injury. However, whether PPARγ activated by curcumin is responsible for the anti-neuroinflammation and neuroprotection on AD remains unclear, and needs to be further investigated. Here, using both APP/PS1 transgenic mice and beta-amyloid-induced neuroinflammation in mixed neuronal/glial cultures, we showed that curcumin significantly alleviated spatial memory deficits in APP/PS1 mice and promoted cholinergic neuronal function in vivo and in vitro. Curcumin also reduced the activation of microglia and astrocytes, as well as cytokine production and inhibited nuclear factor kappa B (NF-κB) signaling pathway, suggesting the beneficial effects of curcumin on AD are attributable to the suppression of neuroinflammation. Attenuation of these beneficial effects occurred when co-administrated with PPARγ antagonist GW9662 or silence of PPARγ gene expression, indicating that PPARγ might be involved in anti-inflammatory effects. Circular dichroism and co-immunoprecipitation analysis showed that curcumin directly bound to PPARγ and increased the transcriptional activity and protein levels of PPARγ. Taking together, these data suggested that PPARγ might be a potential target of curcumin, acting to alleviate neuroinflammation and improve neuronal function in AD. PMID:27594837

  18. Role of plasminogen activator inhibitor-1 in glucocorticoid-induced diabetes and osteopenia in mice.

    PubMed

    Tamura, Yukinori; Kawao, Naoyuki; Yano, Masato; Okada, Kiyotaka; Okumoto, Katsumi; Chiba, Yasutaka; Matsuo, Osamu; Kaji, Hiroshi

    2015-06-01

    Long-term use of glucocorticoids (GCs) causes numerous adverse effects, including glucose/lipid abnormalities, osteoporosis, and muscle wasting. The pathogenic mechanism, however, is not completely understood. In this study, we used plasminogen activator inhibitor-1 (PAI-1)-deficient mice to explore the role of PAI-1 in GC-induced glucose/lipid abnormalities, osteoporosis, and muscle wasting. Corticosterone markedly increased the levels of circulating PAI-1 and the PAI-1 mRNA level in the white adipose tissue of wild-type mice. PAI-1 deficiency significantly reduced insulin resistance and glucose intolerance but not hyperlipidemia induced by GC. An in vitro experiment revealed that active PAI-1 treatment inhibits insulin-induced phosphorylation of Akt and glucose uptake in HepG2 hepatocytes. However, this was not observed in 3T3-L1 adipocytes and C2C12 myotubes, indicating that PAI-1 suppressed insulin signaling in hepatocytes. PAI-1 deficiency attenuated the GC-induced bone loss presumably via inhibition of apoptosis of osteoblasts. Moreover, the PAI-1 deficiency also protected from GC-induced muscle loss. In conclusion, the current study indicated that PAI-1 is involved in GC-induced glucose metabolism abnormality, osteopenia, and muscle wasting in mice. PAI-1 may be a novel therapeutic target to mitigate the adverse effects of GC.

  19. Heat shock protein inhibitors, 17-DMAG and KNK437, enhance arsenic trioxide-induced mitotic apoptosis

    SciTech Connect

    Wu Yichen; Yen Wenyen; Lee, T.-C. Yih, L.-H.

    2009-04-15

    Arsenic trioxide (ATO) has recently emerged as a promising therapeutic agent in leukemia because of its ability to induce apoptosis. However, there is no sufficient evidence to support its therapeutic use for other types of cancers. In this study, we investigated if, and how, 17-dimethylaminoethylamino-17-demethoxy-geldanamycin (17-DMAG), an antagonist of heat shock protein 90 (HSP90), and KNK437, a HSP synthesis inhibitor, potentiated the cytotoxic effect of ATO. Our results showed that cotreatment with ATO and either 17-DMAG or KNK437 significantly increased ATO-induced cell death and apoptosis. siRNA-mediated attenuation of the expression of the inducible isoform of HSP70 (HSP70i) or HSP90{alpha}/{beta} also enhanced ATO-induced apoptosis. In addition, cotreatment with ATO and 17-DMAG or KNK437 significantly increased ATO-induced mitotic arrest and ATO-induced BUBR1 phosphorylation and PDS1 accumulation. Cotreatment also significantly increased the percentage of mitotic cells with abnormal mitotic spindles and promoted metaphase arrest as compared to ATO treatment alone. These results indicated that 17-DMAG or KNK437 may enhance ATO cytotoxicity by potentiating mitotic arrest and mitotic apoptosis possibly through increased activation of the spindle checkpoint.

  20. A Novel Malate Dehydrogenase 2 Inhibitor Suppresses Hypoxia-Inducible Factor-1 by Regulating Mitochondrial Respiration

    PubMed Central

    Jang, Kusik; Kim, Inhyub; Kim, Bo-Kyung; Lee, Kyeong; Won, Misun

    2016-01-01

    We previously reported that hypoxia-inducible factor (HIF)-1 inhibitor LW6, an aryloxyacetylamino benzoic acid derivative, inhibits malate dehydrogenase 2 (MDH2) activity during the mitochondrial tricarboxylic acid (TCA) cycle. In this study, we present a novel MDH2 inhibitor compound 7 containing benzohydrazide moiety, which was identified through structure-based virtual screening of chemical library. Similar to LW6, compound 7 inhibited MDH2 activity in a competitive fashion, thereby reducing NADH level. Consequently, compound 7 reduced oxygen consumption and ATP production during the mitochondrial respiration cycle, resulting in increased intracellular oxygen concentration. Therefore, compound 7 suppressed the accumulation of HIF-1α and expression of its target genes, vascular endothelial growth factor (VEGF) and glucose transporter 1 (GLUT1). Moreover, reduction in ATP content activated AMPK, thereby inactivating ACC and mTOR the downstream pathways. As expected, compound 7 exhibited significant growth inhibition of human colorectal cancer HCT116 cells. Compound 7 demonstrated substantial anti-tumor efficacy in an in vivo xenograft assay using HCT116 mouse model. Taken together, a novel MDH2 inhibitor, compound 7, suppressed HIF-1α accumulation via reduction of oxygen consumption and ATP production, integrating metabolism into anti-cancer efficacy in cancer cells. PMID:27611801

  1. mTOR inhibitors counteract tamoxifen-induced activation of breast cancer stem cells.

    PubMed

    Karthik, Govindasamy-Muralidharan; Ma, Ran; Lövrot, John; Kis, Lorand Levente; Lindh, Claes; Blomquist, Lennart; Fredriksson, Irma; Bergh, Jonas; Hartman, Johan

    2015-10-10

    Breast cancer cells with stem cell characteristics (CSC) are a distinct cell population with phenotypic similarities to mammary stem cells. CSCs are important drivers of tumorigenesis and the metastatic process. Tamoxifen is the most widely used hormonal therapy for estrogen receptor (ER) positive cancers. In our study, tamoxifen was effective in reducing proliferation of ER + adherent cancer cells, but not their CSC population. We isolated, expanded and incubated CSC from seven breast cancers with or without tamoxifen. By genome-wide transcriptional analysis we identified tamoxifen-induced transcriptional pathways associated with ribosomal biogenesis and mRNA translation, both regulated by the mTOR-pathway. We observed induction of the key mTOR downstream targets S6K1, S6RP and 4E-BP1 in-patient derived CSCs by tamoxifen on protein level. Using the mTOR inhibitors rapamycin, everolimus and PF-04691502 (a dual PI3K/mTOR inhibitor) and in combination with tamoxifen, significant reduction in mammosphere formation was observed. Hence, we suggest that the CSC population play a significant role during endocrine resistance through activity of the mTOR pathway. In addition, tamoxifen further stimulates the mTOR-pathway but can be antagonized using mTOR-inhibitors. PMID:26208432

  2. Identification of an Allosteric Small Molecule Inhibitor Selective for Inducible Form of Heat Shock Protein 70

    PubMed Central

    Howe, Matthew K.; Bodoor, Khaldon; Carlson, David A.; Hughes, Philip F.; Alwarawrah, Yazan; Loiselle, David R.; Jaeger, Alex M.; Darr, David B.; Jordan, Jamie L.; Hunter, Lucas M.; Molzberger, Eileen T.; Gobillot, Theodore A.; Thiele, Dennis J.; Brodsky, Jeffrey L.; Spector, Neil L.; Haystead, Timothy A. J.

    2014-01-01

    Summary Inducible Hsp70 (Hsp70i) is overexpressed in a wide spectrum of human tumors and its expression correlates with metastasis, poor outcomes, and resistance to chemotherapy in patients. Identification of small molecule inhibitors selective for Hsp70i could provide new therapeutic tools for cancer treatment. In this work, we used fluorescence-linked enzyme chemoproteomic strategy (FLECS) to identify HS-72, an allosteric inhibitor selective for Hsp70i. HS-72 displays the hallmarks of Hsp70 inhibition in cells, promoting substrate protein degradation and growth inhibition. Importantly, HS-72 is selective for Hsp70i over the closely related constitutively active Hsc70. Studies with purified protein show HS-72 acts as an allosteric inhibitor, reducing ATP affinity. In vivo HS-72 is well-tolerated, showing bioavailability and efficacy, inhibiting tumor growth and promoting survival in a HER2+ model of breast cancer. The HS-72 scaffold is amenable to resynthesis and iteration, suggesting an ideal starting point for a new generation of anticancer therapeutics targeting Hsp70i. PMID:25500222

  3. Selective serotonin reuptake inhibitor antidepressants potentiate methylphenidate (Ritalin)-induced gene regulation in the adolescent striatum.

    PubMed

    Van Waes, Vincent; Beverley, Joel; Marinelli, Michela; Steiner, Heinz

    2010-08-01

    The psychostimulant methylphenidate (Ritalin) is used in conjunction with selective serotonin reuptake inhibitors (SSRIs) in the treatment of medical conditions such as attention-deficit hyperactivity disorder with anxiety/depression comorbidity and major depression. Co-exposure also occurs in patients on SSRIs who use psychostimulant 'cognitive enhancers'. Methylphenidate is a dopamine/norepinephrine reuptake inhibitor that produces altered gene expression in the forebrain; these effects partly mimic gene regulation by cocaine (dopamine/norepinephrine/serotonin reuptake inhibitor). We investigated whether the addition of SSRIs (fluoxetine or citalopram; 5 mg/kg) modified gene regulation by methylphenidate (2-5 mg/kg) in the striatum and cortex of adolescent rats. Our results show that SSRIs potentiate methylphenidate-induced expression of the transcription factor genes zif268 and c-fos in the striatum, rendering these molecular changes more cocaine-like. Present throughout most of the striatum, this potentiation was most robust in its sensorimotor parts. The methylphenidate + SSRI combination also enhanced behavioral stereotypies, consistent with dysfunction in sensorimotor striatal circuits. In so far as such gene regulation is implicated in psychostimulant addiction, our findings suggest that SSRIs may enhance the addiction potential of methylphenidate.

  4. A Novel Malate Dehydrogenase 2 Inhibitor Suppresses Hypoxia-Inducible Factor-1 by Regulating Mitochondrial Respiration.

    PubMed

    Ban, Hyun Seung; Xu, Xuezhen; Jang, Kusik; Kim, Inhyub; Kim, Bo-Kyung; Lee, Kyeong; Won, Misun

    2016-01-01

    We previously reported that hypoxia-inducible factor (HIF)-1 inhibitor LW6, an aryloxyacetylamino benzoic acid derivative, inhibits malate dehydrogenase 2 (MDH2) activity during the mitochondrial tricarboxylic acid (TCA) cycle. In this study, we present a novel MDH2 inhibitor compound 7 containing benzohydrazide moiety, which was identified through structure-based virtual screening of chemical library. Similar to LW6, compound 7 inhibited MDH2 activity in a competitive fashion, thereby reducing NADH level. Consequently, compound 7 reduced oxygen consumption and ATP production during the mitochondrial respiration cycle, resulting in increased intracellular oxygen concentration. Therefore, compound 7 suppressed the accumulation of HIF-1α and expression of its target genes, vascular endothelial growth factor (VEGF) and glucose transporter 1 (GLUT1). Moreover, reduction in ATP content activated AMPK, thereby inactivating ACC and mTOR the downstream pathways. As expected, compound 7 exhibited significant growth inhibition of human colorectal cancer HCT116 cells. Compound 7 demonstrated substantial anti-tumor efficacy in an in vivo xenograft assay using HCT116 mouse model. Taken together, a novel MDH2 inhibitor, compound 7, suppressed HIF-1α accumulation via reduction of oxygen consumption and ATP production, integrating metabolism into anti-cancer efficacy in cancer cells. PMID:27611801

  5. Effect of the 5-lipoxygenase inhibitor ZD2138 on aspirin-induced asthma.

    PubMed Central

    Nasser, S. M.; Bell, G. S.; Foster, S.; Spruce, K. E.; MacMillan, R.; Williams, A. J.; Lee, T. H.; Arm, J. P.

    1994-01-01

    BACKGROUND--The cysteinyl leukotrienes may play a central part in the mechanisms of aspirin-sensitive asthma. Previous work has shown that individuals with aspirin-sensitive asthma have high basal urinary LTE4 levels which increase further upon aspirin ingestion, and that sulphidopeptide leukotriene receptor antagonists attenuate aspirin-induced airflow obstruction. If the cysteinyl leukotrienes cause aspirin-induced asthmatic reactions, inhibition of the 5-lipoxygenase pathway should prevent aspirin-induced bronchospasm. This hypothesis has been tested with ZD2138, a specific non-redox 5-lipoxygenase inhibitor. METHODS--Seven subjects (four men) with aspirin-sensitive asthma with baseline FEV1 values > 67% were studied. ZD2138 (350 mg) or placebo was given on two separate occasions two weeks apart in a randomised double blind fashion. A single dose of aspirin was administered four hours after dosing and FEV1 was measured for six hours. Inhibition of the 5-lipoxygenase pathway by ZD2138 was assessed by measurements of urinary LTE4 levels and ex vivo calcium ionophore stimulated LTB4 generation in whole blood, before administration of drug or placebo and at regular time intervals after dosing and aspirin administration. RESULTS--ZD2138 protected against the aspirin-induced reduction in FEV1 with a 20.3 (4.9)% fall in FEV1 following placebo compared with 4.9 (2.9)% following ZD2138. This was associated with 72% inhibition of ex vivo LTB4 generation in whole blood at 12 hours and a 74% inhibition of the rise in urinary LTE4 excretion at six hours after aspirin ingestion. CONCLUSIONS--In aspirin-sensitive asthma the 5-lipoxygenase inhibitor ZD2138 inhibits the fall in FEV1 induced by aspirin and this is associated with substantial inhibition of 5-lipoxygenase. PMID:8091318

  6. Anti-Ulcer Efficacy of Soluble Epoxide Hydrolase Inhibitor TPPU on Diclofenac-Induced Intestinal Ulcers

    PubMed Central

    Goswami, Sumanta Kumar; Wan, Debin; Yang, Jun; Trindade da Silva, Carlos A.; Morisseau, Christophe; Kodani, Sean D.; Yang, Guang-Yu; Inceoglu, Bora

    2016-01-01

    Proton pump inhibitors such as omeprazole (OME) reduce the severity of gastrointestinal (GI) ulcers induced by nonsteroidal anti-inflammatory drugs (NSAIDs) but can also increase the chance of dysbiosis. The aim of this study was to test the hypothesis that preventive use of a soluble epoxide hydrolase inhibitor (sEHI) such as TPPU can decrease NSAID-induced ulcers by increasing anti-inflammatory epoxyeicosatrienoic acids (EETs). Dose- [10, 30, and 100 mg/kg, by mouth (PO)] and time-dependent (6 and 18 hours) ulcerative effects of diclofenac sodium (DCF, an NSAID) were studied in the small intestine of Swiss Webster mice. Dose-dependent effects of TPPU (0.001–0.1 mg/kg per day for 7 days, in drinking water) were evaluated in DCF-induced intestinal toxicity and compared with OME (20 mg/kg, PO). In addition, the effect of treatment was studied on levels of Hb in blood, EETs in plasma, inflammatory markers such as myeloperoxidase (MPO) in intestinal tissue homogenates, and tissue necrosis factor-α (TNF-α) in serum. DCF dose dependently induced ulcers that were associated with both a significant (P < 0.05) loss of Hb and an increase in the level of MPO and TNF-α, with severity of ulceration highest at 18 hours. Pretreatment with TPPU dose dependently prevented ulcer formation by DCF, increased the levels of epoxy fatty acids, including EETs, and TPPU’s efficacy was comparable to OME. TPPU significantly (P < 0.05) reversed the effect of DCF on the level of Hb, MPO, and TNF-α. Thus sEHI might be useful in the management of NSAID-induced ulcers. PMID:26989141

  7. Anti-Ulcer Efficacy of Soluble Epoxide Hydrolase Inhibitor TPPU on Diclofenac-Induced Intestinal Ulcers.

    PubMed

    Goswami, Sumanta Kumar; Wan, Debin; Yang, Jun; Trindade da Silva, Carlos A; Morisseau, Christophe; Kodani, Sean D; Yang, Guang-Yu; Inceoglu, Bora; Hammock, Bruce D

    2016-06-01

    Proton pump inhibitors such as omeprazole (OME) reduce the severity of gastrointestinal (GI) ulcers induced by nonsteroidal anti-inflammatory drugs (NSAIDs) but can also increase the chance of dysbiosis. The aim of this study was to test the hypothesis that preventive use of a soluble epoxide hydrolase inhibitor (sEHI) such as TPPU can decrease NSAID-induced ulcers by increasing anti-inflammatory epoxyeicosatrienoic acids (EETs). Dose- [10, 30, and 100 mg/kg, by mouth (PO)] and time-dependent (6 and 18 hours) ulcerative effects of diclofenac sodium (DCF, an NSAID) were studied in the small intestine of Swiss Webster mice. Dose-dependent effects of TPPU (0.001-0.1 mg/kg per day for 7 days, in drinking water) were evaluated in DCF-induced intestinal toxicity and compared with OME (20 mg/kg, PO). In addition, the effect of treatment was studied on levels of Hb in blood, EETs in plasma, inflammatory markers such as myeloperoxidase (MPO) in intestinal tissue homogenates, and tissue necrosis factor-α (TNF-α) in serum. DCF dose dependently induced ulcers that were associated with both a significant (P < 0.05) loss of Hb and an increase in the level of MPO and TNF-α, with severity of ulceration highest at 18 hours. Pretreatment with TPPU dose dependently prevented ulcer formation by DCF, increased the levels of epoxy fatty acids, including EETs, and TPPU's efficacy was comparable to OME. TPPU significantly (P < 0.05) reversed the effect of DCF on the level of Hb, MPO, and TNF-α Thus sEHI might be useful in the management of NSAID-induced ulcers. PMID:26989141

  8. Histone deacetylase inhibitor treatment induces 'BRCAness' and synergistic lethality with PARP inhibitor and cisplatin against human triple negative breast cancer cells.

    PubMed

    Ha, Kyungsoo; Fiskus, Warren; Choi, Dong Soon; Bhaskara, Srividya; Cerchietti, Leandro; Devaraj, Santhana G T; Shah, Bhavin; Sharma, Sunil; Chang, Jenny C; Melnick, Ari M; Hiebert, Scott; Bhalla, Kapil N

    2014-07-30

    There is an unmet need to develop new, more effective and safe therapies for the aggressive forms of triple negative breast cancers (TNBCs). While up to 20% of women under 50 years of age with TNBC harbor germline mutations in BRCA1, and these tumors are sensitive to treatment with poly(ADP) ribose polymerase inhibitors, a majority of TNBCs lack BRCA1 mutations or loss of expression. Findings presented here demonstrate that by attenuating the levels of DNA damage response and homologous recombination proteins, pan-histone deacetylase inhibitor (HDI) treatment induces 'BRCAness' and sensitizes TNBC cells lacking BRCA1 to lethal effects of PARP inhibitor or cisplatin. Treatment with HDI also induced hyperacetylation of nuclear hsp90. Similar effects were observed following shRNA-mediated depletion of HDAC3, confirming its role as the deacetylase for nuclear HSP90. Furthermore, cotreatment with HDI and ABT-888 induced significantly more DNA strand breaks than either agent alone, and synergistically induced apoptosis of TNBC cells. Notably, co-treatment with HDI and ABT-888 significantly reduced in vivo tumor growth and markedly improved the survival of mice bearing TNBC cell xenografts. These findings support the rationale to interrogate the clinical activity of this novel combination against human TNBC, irrespective of its expression of mutant BRCA1.

  9. Pharmacologic Profiling of Phosphoinositide 3-Kinase Inhibitors as Mitigators of Ionizing Radiation–Induced Cell Death

    PubMed Central

    Sharlow, Elizabeth R.; Epperly, Michael W.; Lira, Ana; Leimgruber, Stephanie; Skoda, Erin M.; Wipf, Peter; Greenberger, Joel S.

    2013-01-01

    Ionizing radiation (IR) induces genotoxic stress that triggers adaptive cellular responses, such as activation of the phosphoinositide 3-kinase (PI3K)/Akt signaling cascade. Pluripotent cells are the most important population affected by IR because they are required for cellular replenishment. Despite the clear danger to large population centers, we still lack safe and effective therapies to abrogate the life-threatening effects of any accidental or intentional IR exposure. Therefore, we computationally analyzed the chemical structural similarity of previously published small molecules that, when given after IR, mitigate cell death and found a chemical cluster that was populated with PI3K inhibitors. Subsequently, we evaluated structurally diverse PI3K inhibitors. It is remarkable that 9 of 14 PI3K inhibitors mitigated γIR-induced death in pluripotent NCCIT cells as measured by caspase 3/7 activation. A single intraperitoneal dose of LY294002 [2-(4-morpholinyl)-8-phenyl-4H-1-benzopyran-4-one], administered to mice at 4 or 24 hours, or PX-867 [(4S,4aR,5R,6aS,9aR,Z)-11-hydroxy-4-(methoxymethyl)-4a,6a-dimethyl-2,7,10-trioxo-1-(pyrrolidin-1-ylmethylene)-1,2,4,4a,5,6,6a,7,8,9,9a,10-dodecahydroindeno[4,5-H]isochromen-5-yl acetate (CID24798773)], administered 4 hours after a lethal dose of γIR, statistically significantly (P < 0.02) enhanced in vivo survival. Because cell cycle checkpoints are important regulators of cell survival after IR, we examined cell cycle distribution in NCCIT cells after γIR and PI3K inhibitor treatment. LY294002 and PX-867 treatment of nonirradiated cells produced a marked decrease in S phase cells with a concomitant increase in the G1 population. In irradiated cells, LY294002 and PX-867 treatment also decreased S phase and increased the G1 and G2 populations. Treatment with LY294002 or PX-867 decreased γIR-induced DNA damage as measured by γH2AX, suggesting reduced DNA damage. These results indicate pharmacologic inhibition of PI3K after

  10. Inhibitors of ex vivo aggregation of human platelets induced by decompression, during reduced barometric pressure.

    PubMed

    Murayama, M; Kumaroo, K K

    1986-05-15

    It has been shown experimentally ex vivo that human platelet aggregation is induced by decompression (reduced pressure) produced by various means, i.e., reduced barometric pressure, reduced hydrostatic pressure, and reduced hydrodynamic pressure due to Bernoulli's principle. We report here that the spontaneous platelet aggregation induced by reduced barometric pressure (253 torr for three hours) is inhibited by 1:10(7) diluted Japanese herbal plant oil (JHP) and also by two of its major constituents, menthone and menthol with the median inhibitory concentration (IC50) in the millimolar range. These drugs gave essentially similar results when collagen and ADP were used as aggregating agents. Inhibitor concentrations were determined by microscopic examination of platelets in wet preparations when the aggregating stimulus was reduced pressure and by optical aggregometry when collagen and ADP were the aggregating agents. Potential usefulness of these compounds in the prevention of decompression syndrome (DCS) and acute mountain sickness (AMS) are discussed.

  11. 5-Lipoxygenase inhibitors suppress RANKL-induced osteoclast formation via NFATc1 expression.

    PubMed

    Kang, Ju-Hee; Ting, Zheng; Moon, Mi-ran; Sim, Jung-Seon; Lee, Jung-Min; Doh, Kyung-Eun; Hong, Sunhye; Cui, Minghua; Choi, Sun; Chang, Hyeun Wook; Park Choo, Hea-Young; Yim, Mijung

    2015-11-01

    5-Lipoxygenase synthesizes leukotrienes from arachidonic acid. We developed three novel 5-LO inhibitors having a benzoxazole scaffold as a potential anti-osteoclastogenics. They significantly suppressed RANKL-induced osteoclast formation in mouse bone marrow-derived macrophages. Furthermore, one compound, K7, inhibited the bone resorptive activity of osteoclasts. The anti-osteoclastogenic effect of K7 was mainly attributable to reduction in the expression of NFATc1, an essential transcription factor for osteoclast differentiation. K7 inhibited osteoclast formation via ERK and p38 MAPK, as well as NF-κB signaling pathways. K7 reduced lipopolysaccharide (LPS)-induced osteoclast formation in vivo, corroborating the in vitro data. Thus, K7 exerted an inhibitory effect on osteoclast formation in vitro and in vivo, properties that make it a potential candidate for the treatment of bone diseases associated with excessive bone resorption.

  12. Tolerogenic nanoparticles to induce immunologic tolerance: Prevention and reversal of FVIII inhibitor formation.

    PubMed

    Zhang, Ai-Hong; Rossi, Robert J; Yoon, Jeongheon; Wang, Hong; Scott, David W

    2016-03-01

    The immune response of hemophilia A patients to administered FVIII is a major complication that obviates this very therapy. We have recently described the use of synthetic, biodegradable nanoparticles carrying rapamycin and FVIII peptide antigens, to induce antigen-specific tolerance. Herein we test the tolerogenicity of nanoparticles that contains full length FVIII protein in hemophilia A mice, focusing on anti-FVIII humoral immune response. As expected, recipients of tolerogenic nanoparticles remained unresponsive to FVIII despite multiple challenges for up to 6 months. Furthermore, therapeutic treatments in FVIII-immunized mice with pre-existing anti-FVIII antibodies resulted in diminished antibody titers, albeit efficacy required longer therapy with the tolerogenic nanoparticles. Interestingly, durable FVIII-specific tolerance was also achieved in animals co-administered with FVIII admixed with nanoparticles encapsulating rapamycin alone. These results suggest that nanoparticles carrying rapamycin and FVIII can be employed to induce specific tolerance to prevent and even reverse inhibitor formation.

  13. Prevention of chemotherapy-induced alopecia in rats by CDK inhibitors.

    PubMed

    Davis, S T; Benson, B G; Bramson, H N; Chapman, D E; Dickerson, S H; Dold, K M; Eberwein, D J; Edelstein, M; Frye, S V; Gampe Jr, R T; Griffin, R J; Harris, P A; Hassell, A M; Holmes, W D; Hunter, R N; Knick, V B; Lackey, K; Lovejoy, B; Luzzio, M J; Murray, D; Parker, P; Rocque, W J; Shewchuk, L; Veal, J M; Walker, D H; Kuyper, L F

    2001-01-01

    Most traditional cytotoxic anticancer agents ablate the rapidly dividing epithelium of the hair follicle and induce alopecia (hair loss). Inhibition of cyclin-dependent kinase 2 (CDK2), a positive regulator of eukaryotic cell cycle progression, may represent a therapeutic strategy for prevention of chemotherapy-induced alopecia (CIA) by arresting the cell cycle and reducing the sensitivity of the epithelium to many cell cycle-active antitumor agents. Potent small-molecule inhibitors of CDK2 were developed using structure-based methods. Topical application of these compounds in a neonatal rat model of CIA reduced hair loss at the site of application in 33 to 50% of the animals. Thus, inhibition of CDK2 represents a potentially useful approach for the prevention of CIA in cancer patients.

  14. Phenotypic Screening Identifies Protein Synthesis Inhibitors as H-Ras-Nanocluster-Increasing Tumor Growth Inducers.

    PubMed

    Najumudeen, Arafath K; Posada, Itziar M D; Lectez, Benoit; Zhou, Yong; Landor, Sebastian K-J; Fallarero, Adyary; Vuorela, Pia; Hancock, John; Abankwa, Daniel

    2015-12-15

    Ras isoforms H-, N-, and K-ras are each mutated in specific cancer types at varying frequencies and have different activities in cell fate control. On the plasma membrane, Ras proteins are laterally segregated into isoform-specific nanoscale signaling hubs, termed nanoclusters. As Ras nanoclusters are required for Ras signaling, chemical modulators of nanoclusters represent ideal candidates for the specific modulation of Ras activity in cancer drug development. We therefore conducted a chemical screen with commercial and in-house natural product libraries using a cell-based H-ras-nanoclustering FRET assay. Next to established Ras inhibitors, such as a statin and farnesyl-transferase inhibitor, we surprisingly identified five protein synthesis inhibitors as positive regulators. Using commonly employed cycloheximide as a representative compound, we show that protein synthesis inhibition increased nanoclustering and effector recruitment specifically of active H-ras but not of K-ras. Consistent with these data, cycloheximide treatment activated both Erk and Akt kinases and specifically promoted H-rasG12V-induced, but not K-rasG12V-induced, PC12 cell differentiation. Intriguingly, cycloheximide increased the number of mammospheres, which are enriched for cancer stem cells. Depletion of H-ras in combination with cycloheximide significantly reduced mammosphere formation, suggesting an exquisite synthetic lethality. The potential of cycloheximide to promote tumor cell growth was also reflected in its ability to increase breast cancer cell tumors grown in ovo. These results illustrate the possibility of identifying Ras-isoform-specific modulators using nanocluster-directed screening. They also suggest an unexpected feedback from protein synthesis inhibition to Ras signaling, which might present a vulnerability in certain tumor cell types. PMID:26568031

  15. Omeprazole increases the efficacy of a soluble epoxide hydrolase inhibitor in a PGE₂ induced pain model.

    PubMed

    Goswami, Sumanta Kumar; Inceoglu, Bora; Yang, Jun; Wan, Debin; Kodani, Sean D; da Silva, Carlos Antonio Trindade; Morisseau, Christophe; Hammock, Bruce D

    2015-12-15

    Epoxyeicosatrienoic acids (EETs) are potent endogenous analgesic metabolites produced from arachidonic acid by cytochrome P450s (P450s). Metabolism of EETs by soluble epoxide hydrolase (sEH) reduces their activity, while their stabilization by sEH inhibition decreases both inflammatory and neuropathic pain. Here, we tested the complementary hypothesis that increasing the level of EETs through induction of P450s by omeprazole (OME), can influence pain related signaling by itself, and potentiate the anti-hyperalgesic effect of sEH inhibitor. Rats were treated with OME (100mg/kg/day, p.o., 7 days), sEH inhibitor TPPU (3mg/kg/day, p.o.) and OME (100mg/kg/day, p.o., 7 days)+TPPU (3mg/kg/day, p.o., last 3 days of OME dose) dissolved in vehicle PEG400, and their effect on hyperalgesia (increased sensitivity to pain) induced by PGE2 was monitored. While OME treatment by itself exhibited variable effects on PGE2 induced hyperalgesia, it strongly potentiated the effect of TPPU in the same assay. The significant decrease in pain with OME+TPPU treatment correlated with the increased levels of EETs in plasma and increased activities of P450 1A1 and P450 1A2 in liver microsomes. The results show that reducing catabolism of EETs with a sEH inhibitor yielded a stronger analgesic effect than increasing generation of EETs by OME, and combination of both yielded the strongest pain reducing effect under the condition of this study. PMID:26522832

  16. A novel PKC-ι inhibitor abrogates cell proliferation and induces apoptosis in neuroblastoma.

    PubMed

    Pillai, Prajit; Desai, Shraddha; Patel, Rekha; Sajan, Mini; Farese, Robert; Ostrov, David; Acevedo-Duncan, Mildred

    2011-05-01

    Protein Kinase C-iota (PKC-ι), an atypical protein kinase C isoform manifests its potential as an oncogene by targeting various aspects of cancer cells such as growth, invasion and survival. PKC-ι confers resistance to drug-induced apoptosis in cancer cells. The acquisition of drug resistance is a major obstacle to good prognosis in neuroblastoma. The focus of this research was to identify the efficacy of [4-(5-amino-4-carbamoylimidazol-1-yl)-2,3-dihydroxycyclopentyl] methyl dihydrogen phosphate (ICA-1) as a novel PKC-ι inhibitor in neuroblastoma cell proliferation and apoptosis. ICA-1 specifically inhibits the activity of PKC-ι but not that of PKC-zeta (PKC-ζ), the closely related atypical PKC family member. The IC(50) for the kinase activity assay was approximately 0.1μM which is 1000 times less than that of aurothiomalate, a known PKC-ι inhibitor. Cyclin dependent kinase 7 (Cdk7) phosphorylates cyclin dependent kinases (cdks) and promotes cell proliferation. Our data shows that PKC-ι is an in vitro Cdk7 kinase and the phosphorylation of Cdk7 by PKC-ι was potently inhibited by ICA-1. Furthermore, our data shows that neuroblastoma cells proliferate via a PKC-ι/Cdk7/cdk2 cell signaling pathway and ICA-1 mediates its antiproliferative effects by inhibiting this pathway. ICA-1 (0.1μM) inhibited the in vitro proliferation of BE(2)-C neuroblastoma cells by 58% (P=0.01). Additionally, ICA-1 also induced apoptosis in neuroblastoma cells. Interestingly, ICA-1 did not affect the proliferation of normal neuronal cells suggesting its potential as chemotherapeutic with low toxicity. Hence, our results emphasize the potential of ICA-1 as a novel PKC-ι inhibitor and chemotherapeutic agent for neuroblastoma.

  17. Phenotypic Screening Identifies Protein Synthesis Inhibitors as H-Ras-Nanocluster-Increasing Tumor Growth Inducers.

    PubMed

    Najumudeen, Arafath K; Posada, Itziar M D; Lectez, Benoit; Zhou, Yong; Landor, Sebastian K-J; Fallarero, Adyary; Vuorela, Pia; Hancock, John; Abankwa, Daniel

    2015-12-15

    Ras isoforms H-, N-, and K-ras are each mutated in specific cancer types at varying frequencies and have different activities in cell fate control. On the plasma membrane, Ras proteins are laterally segregated into isoform-specific nanoscale signaling hubs, termed nanoclusters. As Ras nanoclusters are required for Ras signaling, chemical modulators of nanoclusters represent ideal candidates for the specific modulation of Ras activity in cancer drug development. We therefore conducted a chemical screen with commercial and in-house natural product libraries using a cell-based H-ras-nanoclustering FRET assay. Next to established Ras inhibitors, such as a statin and farnesyl-transferase inhibitor, we surprisingly identified five protein synthesis inhibitors as positive regulators. Using commonly employed cycloheximide as a representative compound, we show that protein synthesis inhibition increased nanoclustering and effector recruitment specifically of active H-ras but not of K-ras. Consistent with these data, cycloheximide treatment activated both Erk and Akt kinases and specifically promoted H-rasG12V-induced, but not K-rasG12V-induced, PC12 cell differentiation. Intriguingly, cycloheximide increased the number of mammospheres, which are enriched for cancer stem cells. Depletion of H-ras in combination with cycloheximide significantly reduced mammosphere formation, suggesting an exquisite synthetic lethality. The potential of cycloheximide to promote tumor cell growth was also reflected in its ability to increase breast cancer cell tumors grown in ovo. These results illustrate the possibility of identifying Ras-isoform-specific modulators using nanocluster-directed screening. They also suggest an unexpected feedback from protein synthesis inhibition to Ras signaling, which might present a vulnerability in certain tumor cell types.

  18. Identification of H7 as a novel peroxiredoxin I inhibitor to induce differentiation of leukemia cells

    PubMed Central

    Qin, Dongjun; Chen, Yingyi; Liu, Chuanxu; Xia, Li; Wang, Tongdan; Lei, Hu; Yu, Yun; Huang, Min; Tong, Yin; Xu, Hanzhang; Gao, Fenghou

    2016-01-01

    Identifying novel targets to enhance leukemia-cell differentiation is an urgent requirment. We have recently proposed that inhibiting the antioxidant enzyme peroxiredoxin I (Prdx I) may induce leukemia-cell differentiation. However, this concept remains to be confirmed. In this work, we identified H7 as a novel Prdx I inhibitor through virtual screening, in vitro activity assay, and surface plasmon resonance assay. Cellular thermal shift assay showed that H7 directly bound to Prdx I but not to Prdxs II–V in cells. H7 treatment also increased reactive oxygen species (ROS) level and cell differentiation in leukemia cells, as reflected by the upregulation of the cell surface differentiation marker CD11b/CD14 and the morphological maturation of cells. The differentiation-induction effect of H7 was further observed in some non-acute promyelocytic leukemia (APL) and primary leukemia cells apart from APL NB4 cells. Moreover, the ROS scavenger N-acetyl cysteine significantly reversed the H7-induced cell differentiation. We demonstrated as well that H7-induced cell differentiation was associated with the activation of the ROS-Erk1/2-C/EBPβ axis. Finally, we showed H7 treatment induced cell differentiation in an APL mouse model. All of these data confirmed that Prdx I was novel target for inducing leukemia-cell differentiation and that H7 was a novel lead compound for optimizing Prdx I inhibition. PMID:26716647

  19. Salubrinal, ER stress inhibitor, attenuates kainic acid-induced hippocampal cell death.

    PubMed

    Kim, Jung Soo; Heo, Rok Won; Kim, Hwajin; Yi, Chin-Ok; Shin, Hyun Joo; Han, Jong Woo; Roh, Gu Seob

    2014-10-01

    Kainic acid (KA)-induced neuronal death is closely linked to endoplasmic reticulum (ER) and mitochondrial dysfunction. Parkin is an ubiquitin E3 ligase that mediates the ubiquitination of the Bcl-2 family of proteins and its mutations are associated with neuronal apoptosis in neurodegenerative diseases. We investigated the effect of salubrinal, an ER stress inhibitor, on the regulation of ER stress and mitochondrial apoptosis induced by KA, in particular, by controlling parkin expression. We showed that salubrinal significantly reduced seizure activity and increased survival rates of mice with KA-induced seizures. We found that salubrinal protected neurons against apoptotic death by reducing expression of mitochondrial apoptotic factors and elF2α-ATF4-CHOP signaling proteins. Interestingly, we showed that salubrinal decreased the KA-induced parkin expression and inhibited parkin translocation to mitochondria, which suggests that parkin may regulate a cross-talk between ER and mitochondria. Collectively, inhibition of ER stress attenuates mitochondrial apoptotic and ER stress pathways and controls parkin-mediated neuronal death following KA-induced seizures. PMID:24728926

  20. Sorafenib, a multikinase inhibitor, induces formation of stress granules in hepatocarcinoma cells

    PubMed Central

    Adjibade, Pauline; St-Sauveur, Valérie Grenier; Huberdeau, Miguel Quevillon; Fournier, Marie-Josée; Savard, Andreanne; Coudert, Laetitia; Khandjian, Edouard W.; Mazroui, Rachid

    2015-01-01

    Stress granules (SGs) are cytoplasmic RNA multimeric bodies that form under stress conditions known to inhibit translation initiation. In most reported stress cases, the formation of SGs was associated with the cell recovery from stress and survival. In cells derived from cancer, SGs formation was shown to promote resistance to either proteasome inhibitors or 5-Fluorouracil used as chemotherapeutic agents. Despite these studies, the induction of SGs by chemotherapeutic drugs contributing to cancer cells resistance is still understudied. Here we identified sorafenib, a tyrosine kinase inhibitor used to treat hepatocarcinoma, as a potent chemotherapeutic inducer of SGs. The formation of SGs in sorafenib-treated hepatocarcionoma cells correlates with inhibition of translation initiation; both events requiring the phosphorylation of the translation initiation factor eIF2α. Further characterisation of the mechanism of sorafenib-induced SGs revealed PERK as the main eIF2α kinase responsible for SGs formation. Depletion experiments support the implication of PERK-eIF2α-SGs pathway in hepatocarcinoma cells resistance to sorafenib. This study also suggests the existence of an unexpected complex regulatory balance between SGs and phospho-eIF2α where SGs dampen the activation of the phospho-eIF2α-downstream ATF4 cell death pathway. PMID:26556863

  1. Histone deacetylase inhibitor, CG200745, attenuates cardiac hypertrophy and fibrosis in DOCA-induced hypertensive rats

    PubMed Central

    Lee, Eunjo; Song, Min-ji; Lee, Hae-Ahm; Kang, Seol-Hee; Kim, Mina; Yang, Eun Kyoung; Lee, Do Young; Ro, Seonggu; Cho, Joong Myung

    2016-01-01

    CG200745 is a novel inhibitor of histone deacetylases (HDACs), initially developed for treatment of various hematological and solid cancers. Because it is water-soluble, it can be administered orally. We hypothesized that the HDAC inhibitor, CG200745, attenuates cardiac hypertrophy and fibrosis in deoxycorticosterone acetate (DOCA)-induced hypertensive rats. For establishment of hypertension, 40 mg/kg of DOCA was subcutaneously injected four times weekly into Sprague-Dawley rats. All the rats used in this study including those in the sham group had been unilaterally nephrectomized and allowed free access to drinking water containing 1% NaCl. Systolic blood pressure was measured by the tail-cuff method. Blood chemistry including sodium, potassium, glucose, triglyceride, and cholesterol levels was analyzed. Sections of the heart were visualized after trichrome and hematoxylin and eosin stain. The expression of hypertrophic genes such as atrial natriuretic peptide A (Nppa) and atrial natriuretic peptide B (Nppb) in addition to fibrotic genes such as Collagen-1, Collagen-3, connective tissue growth factor (Ctgf), and Fibronectin were measured by quantitative real-time PCR (qRT-PCR). Injection of DOCA increased systolic blood pressure, heart weight, and cardiac fibrosis, which was attenuated by CG200745. Neither DOCA nor CG200745 affected body weight, vascular contraction and relaxation responses, and blood chemistry. Injection of DOCA increased expression of both hypertrophic and fibrotic genes, which was abrogated by CG200745. These results indicate that CG200745 attenuates cardiac hypertrophy and fibrosis in DOCA-induced hypertensive rats.

  2. Novel Nox inhibitor of oxLDL-induced reactive oxygen species formation in human endothelial cells.

    PubMed

    Stielow, Claudia; Catar, Rusan A; Muller, Gregor; Wingler, Kirstin; Scheurer, Peter; Schmidt, Harald H H W; Morawietz, Henning

    2006-05-26

    In this study, we investigated effects of a novel NAD(P)H oxidase (Nox)-inhibitor 3-benzyl-7-(2-benzoxazolyl)thio-1,2,3-triazolo[4,5-d]pyrimidine (VAS2870) on oxidized low-density lipoprotein (oxLDL)-mediated reactive oxygen species (ROS) formation in human endothelial cells. Primary cultures of human umbilical vein endothelial cells were cultured to confluence and ROS formation was induced with 50microg/ml oxLDL for 2h. ROS formation was detected by chemiluminescence (CL) using the Diogenes reagent. OxLDL induced ROS formation in human endothelial cells (171+/-12%; n=10, P<0.05 vs. control). This augmented ROS formation in response to oxLDL was completely inhibited by the Nox inhibitor VAS2870 (101+/-9%; n=7, P<0.05 vs. oxLDL). Similar results were obtained with superoxide dismutase (91+/-7%; n=7, P<0.05 vs. oxLDL). However, the Nox4 mRNA expression level was neither changed by oxLDL nor VAS2870. We conclude that VAS2870 could provide a novel strategy to inhibit the augmented endothelial superoxide anion formation in response to cardiovascular risk factors. PMID:16603125

  3. Histone deacetylase inhibitor, CG200745, attenuates cardiac hypertrophy and fibrosis in DOCA-induced hypertensive rats

    PubMed Central

    Lee, Eunjo; Song, Min-ji; Lee, Hae-Ahm; Kang, Seol-Hee; Kim, Mina; Yang, Eun Kyoung; Lee, Do Young; Ro, Seonggu; Cho, Joong Myung

    2016-01-01

    CG200745 is a novel inhibitor of histone deacetylases (HDACs), initially developed for treatment of various hematological and solid cancers. Because it is water-soluble, it can be administered orally. We hypothesized that the HDAC inhibitor, CG200745, attenuates cardiac hypertrophy and fibrosis in deoxycorticosterone acetate (DOCA)-induced hypertensive rats. For establishment of hypertension, 40 mg/kg of DOCA was subcutaneously injected four times weekly into Sprague-Dawley rats. All the rats used in this study including those in the sham group had been unilaterally nephrectomized and allowed free access to drinking water containing 1% NaCl. Systolic blood pressure was measured by the tail-cuff method. Blood chemistry including sodium, potassium, glucose, triglyceride, and cholesterol levels was analyzed. Sections of the heart were visualized after trichrome and hematoxylin and eosin stain. The expression of hypertrophic genes such as atrial natriuretic peptide A (Nppa) and atrial natriuretic peptide B (Nppb) in addition to fibrotic genes such as Collagen-1, Collagen-3, connective tissue growth factor (Ctgf), and Fibronectin were measured by quantitative real-time PCR (qRT-PCR). Injection of DOCA increased systolic blood pressure, heart weight, and cardiac fibrosis, which was attenuated by CG200745. Neither DOCA nor CG200745 affected body weight, vascular contraction and relaxation responses, and blood chemistry. Injection of DOCA increased expression of both hypertrophic and fibrotic genes, which was abrogated by CG200745. These results indicate that CG200745 attenuates cardiac hypertrophy and fibrosis in DOCA-induced hypertensive rats. PMID:27610034

  4. Histone deacetylase inhibitor, CG200745, attenuates cardiac hypertrophy and fibrosis in DOCA-induced hypertensive rats.

    PubMed

    Lee, Eunjo; Song, Min-Ji; Lee, Hae-Ahm; Kang, Seol-Hee; Kim, Mina; Yang, Eun Kyoung; Lee, Do Young; Ro, Seonggu; Cho, Joong Myung; Kim, Inkyeom

    2016-09-01

    CG200745 is a novel inhibitor of histone deacetylases (HDACs), initially developed for treatment of various hematological and solid cancers. Because it is water-soluble, it can be administered orally. We hypothesized that the HDAC inhibitor, CG200745, attenuates cardiac hypertrophy and fibrosis in deoxycorticosterone acetate (DOCA)-induced hypertensive rats. For establishment of hypertension, 40 mg/kg of DOCA was subcutaneously injected four times weekly into Sprague-Dawley rats. All the rats used in this study including those in the sham group had been unilaterally nephrectomized and allowed free access to drinking water containing 1% NaCl. Systolic blood pressure was measured by the tail-cuff method. Blood chemistry including sodium, potassium, glucose, triglyceride, and cholesterol levels was analyzed. Sections of the heart were visualized after trichrome and hematoxylin and eosin stain. The expression of hypertrophic genes such as atrial natriuretic peptide A (Nppa) and atrial natriuretic peptide B (Nppb) in addition to fibrotic genes such as Collagen-1, Collagen-3, connective tissue growth factor (Ctgf), and Fibronectin were measured by quantitative real-time PCR (qRT-PCR). Injection of DOCA increased systolic blood pressure, heart weight, and cardiac fibrosis, which was attenuated by CG200745. Neither DOCA nor CG200745 affected body weight, vascular contraction and relaxation responses, and blood chemistry. Injection of DOCA increased expression of both hypertrophic and fibrotic genes, which was abrogated by CG200745. These results indicate that CG200745 attenuates cardiac hypertrophy and fibrosis in DOCA-induced hypertensive rats. PMID:27610034

  5. Sorafenib, a multikinase inhibitor, induces formation of stress granules in hepatocarcinoma cells.

    PubMed

    Adjibade, Pauline; St-Sauveur, Valérie Grenier; Quevillon Huberdeau, Miguel; Fournier, Marie-Josée; Savard, Andreanne; Coudert, Laetitia; Khandjian, Edouard W; Mazroui, Rachid

    2015-12-22

    Stress granules (SGs) are cytoplasmic RNA multimeric bodies that form under stress conditions known to inhibit translation initiation. In most reported stress cases, the formation of SGs was associated with the cell recovery from stress and survival. In cells derived from cancer, SGs formation was shown to promote resistance to either proteasome inhibitors or 5-Fluorouracil used as chemotherapeutic agents. Despite these studies, the induction of SGs by chemotherapeutic drugs contributing to cancer cells resistance is still understudied. Here we identified sorafenib, a tyrosine kinase inhibitor used to treat hepatocarcinoma, as a potent chemotherapeutic inducer of SGs. The formation of SGs in sorafenib-treated hepatocarcionoma cells correlates with inhibition of translation initiation; both events requiring the phosphorylation of the translation initiation factor eIF2α. Further characterisation of the mechanism of sorafenib-induced SGs revealed PERK as the main eIF2α kinase responsible for SGs formation. Depletion experiments support the implication of PERK-eIF2α-SGs pathway in hepatocarcinoma cells resistance to sorafenib. This study also suggests the existence of an unexpected complex regulatory balance between SGs and phospho-eIF2α where SGs dampen the activation of the phospho-eIF2α-downstream ATF4 cell death pathway.

  6. Development of decision tree models for substrates, inhibitors, and inducers of p-glycoprotein.

    PubMed

    Hammann, Felix; Gutmann, Heike; Jecklin, Ursula; Maunz, Andreas; Helma, Christoph; Drewe, Juergen

    2009-05-01

    In silico classification of new compounds for certain properties is a useful tool to guide further experiments or compound selection. Interaction of new compounds with the efflux pump P-glycoprotein (P-gp) is an important drug property determining tissue distribution and the potential for drug-drug interactions. We present three datasets on substrate, inhibitor, and inducer activities for P-gp (n = 471) obtained from a literature search which we compared to an existing evaluation of the Prestwick Chemical Library with the calcein-AM assay (retrieved from PubMed). Additionally, we present decision tree models of these activities with predictive accuracies of 77.7 % (substrates), 86.9 % (inhibitors), and 90.3 % (inducers) using three algorithms (CHAID, CART, and C4.5). We also present decision tree models of the calcein-AM assay (79.9 %). Apart from a comprehensive dataset of P-gp interacting compounds, our study provides evidence of the efficacy of logD descriptors and of two algorithms not commonly used in pharmacological QSAR studies (CART and CHAID). PMID:19519342

  7. Farnesyltransferase inhibitor, tipifarnib, prevents galactosamine/lipopolysaccharide-induced acute liver failure.

    PubMed

    Shirozu, Kazuhiro; Hirai, Shuichi; Tanaka, Tomokazu; Hisaka, Shinsuke; Kaneki, Masao; Ichinose, Fumito

    2014-12-01

    Acute liver failure (ALF) is a fatal syndrome associated with massive hepatocyte death. There is no cure for ALF except liver transplantation. Protein farnesylation is a lipid modification of cysteine residues that is catalyzed by farnesyltransferase (FTase) and has been proposed as an integral component of acute inflammation. Previously, we have demonstrated that FTase inhibitors improve survival in mouse models of endotoxemia and sepsis. Here we studied the effects of FTase inhibitor, tipifarnib, on galactosamine (GalN)/lipopolysaccharide (LPS)-induced ALF. The effects of tipifarnib (10 mg/kg, i.p.) were studied in GalN (400 mg/kg, i.p.)- and LPS (3 μg/kg)-challenged mice by histological and biochemical analyses. Galactosamine/LPS administration caused prominent liver injury characterized by the increased plasma alanine aminotransferase and aspartic aminotransferase levels, leading to significant mortality in mice. Tipifarnib inhibited GalN/LPS-induced caspase 3 activation, inflammatory cytokine production, and c-Jun N-terminal kinase phosphorylation in the liver. On the other hand, tipifarnib upregulated antiapoptotic protein, Bcl-xL, in the liver after GalN/LPS challenge. Tipifarnib also protected primary hepatocytes from GalN/tumor necrosis factor α-induced cell death by inhibiting caspase 3 activation and upregulating antiapoptotic proteins. Galactosamine/LPS-induced liver injury was associated with increased protein farnesylation in the liver. Tipifarnib prevented protein farnesylation in the liver and markedly attenuated liver injury and mortality in GalN/LPS-challenged mice. These results suggest that protein farnesylation is a novel potential molecular target to prevent hepatocyte death and acute inflammatory liver failure in fulminant hepatitis. PMID:25046541

  8. Bowman-Birk protease inhibitor from soybeans enhances cisplatin-induced cytotoxicity in human mesothelioma cells.

    PubMed

    Kashiwagi, Korehito; Virgona, Nantiga; Yamada, Jin; Sato, Ayami; Ota, Masako; Yazawa, Takuya; Yano, Tomohiro

    2011-07-01

    Malignant mesothelioma (MM) is an aggressive cancer with no effective treatment options. Enforced expression of the gap junction (GJ) component connexin 43 (Cx43) increases the sensitivity of MM cells to cisplatin. Bowman-Birk protease inhibitor (BBI) induces the restoration of Cx43 in several types of tumor cells. In this study, we examined the capability of BBI to enhance the cytotoxic effect of cisplatin in MM cells via the induction of Cx43. Human MM H28 cells were used. Cell viability was evaluated by a WST-1 assay and proteasomal activity was determined by fluorometric analysis. Protein and mRNA levels were determined by immunoblot analysis and real-time RT-PCR, respectively. GJ function mediated by Cx43 was evaluated using the scrape-loading method. BBI effectively inhibited H28 cell growth in a dose-dependent manner (200-400 μg/ml). In parallel with the growth inhibition, Cx43 levels (mRNA and protein) and GJ function were elevated by BBI treatment. Knockdown of BBI-induced Cx43 by an antisense nucleotide treatment almost cancelled the growth inhibition. BBI enhanced cisplatin-induced cytotoxicity in H28 cells, and down-regulation of Cx43 by the antisense nucleotide treatment abrogated the enhancing effect of BBI. The induction of Cx43 by BBI contributed to Src inactivation and subsequent induction of Bax. Furthermore, an Src inhibitor (SU6656) also enhanced cisplatin-induced cytotoxicity in H28 cells. These results suggest that BBI improves the cytotoxic efficacy of cisplatin in H28 cells via the inhibition of Src signaling.

  9. Bowman-Birk protease inhibitor from soybeans enhances cisplatin-induced cytotoxicity in human mesothelioma cells

    PubMed Central

    KASHIWAGI, KOREHITO; VIRGONA, NANTIGA; YAMADA, JIN; SATO, AYAMI; OTA, MASAKO; YAZAWA, TAKUYA; YANO, TOMOHIRO

    2011-01-01

    Malignant mesothelioma (MM) is an aggressive cancer with no effective treatment options. Enforced expression of the gap junction (GJ) component connexin 43 (Cx43) increases the sensitivity of MM cells to cisplatin. Bowman-Birk protease inhibitor (BBI) induces the restoration of Cx43 in several types of tumor cells. In this study, we examined the capability of BBI to enhance the cytotoxic effect of cisplatin in MM cells via the induction of Cx43. Human MM H28 cells were used. Cell viability was evaluated by a WST-1 assay and proteasomal activity was determined by fluorometric analysis. Protein and mRNA levels were determined by immunoblot analysis and real-time RT-PCR, respectively. GJ function mediated by Cx43 was evaluated using the scrape-loading method. BBI effectively inhibited H28 cell growth in a dose-dependent manner (200–400 μg/ml). In parallel with the growth inhibition, Cx43 levels (mRNA and protein) and GJ function were elevated by BBI treatment. Knockdown of BBI-induced Cx43 by an antisense nucleotide treatment almost cancelled the growth inhibition. BBI enhanced cisplatin-induced cytotoxicity in H28 cells, and down-regulation of Cx43 by the antisense nucleotide treatment abrogated the enhancing effect of BBI. The induction of Cx43 by BBI contributed to Src inactivation and subsequent induction of Bax. Furthermore, an Src inhibitor (SU6656) also enhanced cisplatin-induced cytotoxicity in H28 cells. These results suggest that BBI improves the cytotoxic efficacy of cisplatin in H28 cells via the inhibition of Src signaling. PMID:22977565

  10. Microporation is an efficient method for siRNA-induced knockdown of PEX5 in HepG2 cells: evaluation of the transfection efficiency, the PEX5 mRNA and protein levels and induction of peroxisomal deficiency.

    PubMed

    Ahlemeyer, Barbara; Vogt, Julia-Franziska; Michel, Vera; Hahn-Kohlberger, Petra; Baumgart-Vogt, Eveline

    2014-11-01

    The pathomechanism of peroxisomal biogenesis disorders (PBDs), a group of inherited autosomal recessive diseases with mutations of peroxin (PEX) genes, is not yet fully understood. Therefore, several knockout models, e.g., the PEX5 knockout mouse, have been generated exhibiting a complete loss of peroxisomal function. In this study, we wanted to knockdown PEX5 using the siRNA technology (1) to mimic milder forms of PBDs in which the mutated peroxin has some residual function and (2) to analyze the cellular consequences of a reduction of the PEX5 protein without adaption during the development as it is the case in a knockout animal. First, we tried to optimize the transfection of the hepatoma cell line HepG2 with PEX5 siRNA using different commercially available liposomal and non-liposomal transfection reagents (Lipofectamine(®) 2000, FuGENE 6, HiPerFect(®), INTERFERin™, RiboJuice™) as well as microporation using the Neon™ Transfection system. Microporation was found to be superior to the transfection reagents with respect to the transfection efficiency (100 vs. 0-70%), to the reduction of PEX5 mRNA (by 90 vs. 0-50%) and PEX5 protein levels (by 70 vs. 0-50%). Interestingly, we detected that a part of the cleaved PEX5 mRNA still existed as 3' fragment (15%) 24 h after microporation. Using microporation, we further analyzed whether the reduced PEX5 protein level impaired peroxisomal function. We indeed detected a reduced targeting of SKL-tagged proteins into peroxisomes as well as an increased oxidative stress as found in PBD patients and respective knockout mouse models. Knockdown of the PEX5 protein and functional consequences were at a maximum 48 h after microporation. Thereafter, the PEX5 protein was resynthesized, which may allow the temporal analysis of the loss as well as the reconstitution of peroxisomes in the future. In conclusion, we propose microporation as an efficient and reproducible method to transfect HepG2 cells with PEX5 siRNA. We succeeded

  11. Immunochemical identity of peroxisomal enoyl-CoA hydratase with the peroxisome-proliferation -associated 80,000 mol wt polypeptide in rat liver

    PubMed Central

    Reddy, MK; Qreshi, SA; Hollenberg, PF; Reddy, JK

    1981-01-01

    Peroxisome proliferators, which induce proliferation of hepatic peroxisomes, have been shown previously to cause a marked increase in an 80,000 mol wt polypeptide predominantly in the light mitochondrial and microsomal fractions of liver of rodents. We now present evidence to show that this hepatic peroxisome-proliferation-associated polypeptide, referred to as polypeptide PPA-80, is immunochemically identical with the multifunctional peroxisome protein displaying heat-labile enoyl-CoA hydratase activity. This conclusion is based on the following observations: (a) the purified polypeptide PPA-80 and the heat- labile enoyl-CoA hydratase from livers of rats treated with the peroxisome proliferators Wy-14,643 {[4-chloro-6(2,3-xylidino)-2-pyrimidinylthio]acetic acid} exhibit identical minimum molecular weights of approximately 80,000 on SDS polyacrylamide gel electrophoresis; (b) these two proteins are immunochemically identical on the basis of ouchterlony double diffusion, immunotitration, rocket immunoelectrophoresis, and crossed immunoelectrophoresis analysis; and (c) the immunoprecipitates formed by antibodies to polypeptide PPA-80 when dissociated on a sephadex G-200 column yield enoyl-CoA hydratase activity. Whether the polypeptide PPA-80 exhibits the activity of other enzyme(s) of the peroxisomal β-oxidation system such as fatty acyl-CoA oxidase activity or displays immunochemical identity with such enzymes remains to be determined. The availability of antibodies to polypeptide PPA-80 and enoyl-CoA hydratase facilitated immunofluorescent and immunocytochemical localization of the polypeptide PPA- 80 and enoyl-CoA hydratase in the rat liver. The indirect immunofluorescent studies with these antibodies provided direct visual evidence for the marked induction of polypeptide PPA-80 and enoyl-CoA hydratase in the livers of rats treated with Wy-14,643. The present studies also provide immunocytochemical evidence for the localization of polypeptide PPA- 80 and the

  12. CZ415, a Highly Selective mTOR Inhibitor Showing in Vivo Efficacy in a Collagen Induced Arthritis Model.

    PubMed

    Cansfield, Andrew D; Ladduwahetty, Tammy; Sunose, Mihiro; Ellard, Katie; Lynch, Rosemary; Newton, Anthea L; Lewis, Ann; Bennett, Gavin; Zinn, Nico; Thomson, Douglas W; Rüger, Anne J; Feutrill, John T; Rausch, Oliver; Watt, Alan P; Bergamini, Giovanna

    2016-08-11

    CZ415, a potent ATP-competitive mTOR inhibitor with unprecedented selectivity over any other kinase is described. In addition to a comprehensive characterization of its activities in vitro, in vitro ADME, and in vivo pharmacokinetic data are reported. The suitability of this inhibitor for studying in vivo mTOR biology is demonstrated in a mechanistic mouse model monitoring mTOR proximal downstream phosphorylation signaling. Furthermore, the compound reported here is the first ATP-competitive mTOR inhibitor described to show efficacy in a semitherapeutic collagen induced arthritis (CIA) mouse model. PMID:27563401

  13. Nuclear Factor Kappa B Activation and Peroxisome Proliferator-activated Receptor Transactivational Effects of Chemical Components of the Roots of Polygonum multiflorum

    PubMed Central

    Sun, Ya Nan; Li, Wei; Song, Seok Bean; Yan, Xi Tao; Yang, Seo Young; Kim, Young Ho

    2016-01-01

    Background: Polygonum multiflorum is well-known as “Heshouwu” in traditional Chinese herbal medicine. In Northeast Asia, it is often used as a tonic to prevent premature aging of the kidney and liver, tendons, and bones and strengthening of the lower back and knees. Objective: To research the anti-inflammatory activities of components from P. multiflorum. Materials and Methods: The compounds were isolated by a combination of silica gel and YMC R-18 column chromatography, and their structures were identified by analysis of spectroscopic data (1D, 2D-nuclear magnetic resonance, and mass spectrometry). The anti-inflammatory activities of the isolated compounds 1−15 were evaluated by luciferase reporter gene assays. Results: Fifteen compounds (1–15) were isolated from the roots of P. multiflorum. Compounds 1−5 and 14−15 significantly inhibited tumor necrosis factor-α-induced nuclear factor kappa B-luciferase activity, with IC50 values of 24.16-37.56 μM. Compounds 1−5 also greatly enhanced peroxisome proliferator-activated receptors transcriptional activity with EC50 values of 18.26−31.45 μM. Conclusion: The anthraquinone derivatives were the active components from the roots of P. multiflorum as an inhibitor on inflammation-related factors in human hepatoma cells. Therefore, we suggest that the roots of P. multiflorum can be used to treat natural inflammatory diseases. SUMMARY This study presented that fifteen compounds (1-15) isolated from the roots of Polygonum multiflrum exert signifiant anti inflmmatory effects by inhibiting TNF α induced NF κB activation and PPARs transcription. Abbreviation used: NF κB: Nuclear factor kappa B, PPARs: Peroxisome proliferator activated receptors, PPREs: Peroxisome proliferator response elements, TNF α: Tumor necrosis factor α, ESI-MS: Electrospray ionization mass spectrometry, HepG2: Human hepatoma cells PMID:27019559

  14. Plant density and nutrient availability constrain constitutive and wound-induced expression of trypsin inhibitors in Brassica napus.

    PubMed

    Cipollini, D F; Bergelson, J

    2001-03-01

    We investigated the effects of plant density on plant size, leaf total soluble protein content, and constitutive and wound-induced levels of proteinaceous trypsin inhibitors in pot-grown Brassica napus seedlings in two greenhouse studies. We manipulated plant density by varying the number of intraspecific neighbors surrounding a target plant in the center of each pot. In general, constitutive and induced levels of trypsin inhibitors were significantly reduced by competition in a density-dependent manner, to the extent that induction was greatly reduced or abolished in target plants surrounded by six neighbors. To investigate whether the effects of plant density on inhibitor production were mediated by nutrient availability, we manipulated the concentration of a complete fertilizer applied to target plants surrounded by six neighbors in two greenhouse studies. In general, constitutive and wound-induced levels of inhibitors in plants surrounded by six neighbors were increased by nutrient addition in a dose-dependent manner, such that wound-induction was completely restored in competing plants under conditions of high nutrient availability. Leaf total soluble protein content, measured only in the second trial of each experiment, was not affected by any of the treatments. The effects of plant density, nutrient addition, and wounding on inhibitor levels in all experiments were independent of their effects on above-ground plant size at the time of wounding. Overall, our results suggest that decreasing nutrient availability mediates the density-dependent reductions in inhibitor levels in B. napus seedings.

  15. Selective Inducible Nitric Oxide Synthase Inhibitor Reversed Zinc Chloride-Induced Spatial Memory Impairment via Increasing Cholinergic Marker Expression.

    PubMed

    Tabrizian, Kaveh; Azami, Kian; Belaran, Maryam; Soodi, Maliheh; Abdi, Khosrou; Fanoudi, Sahar; Sanati, Mehdi; Mottaghi Dastjerdi, Negar; Soltany Rezaee-Rad, Mohammad; Sharifzadeh, Mohammad

    2016-10-01

    Zinc, an essential micronutrient and biochemical element of the human body, plays structural, catalytic, and regulatory roles in numerous physiological functions. In the current study, the effects of a pretraining oral administration of zinc chloride (10, 25, and 50 mg/kg) for 14 consecutive days and post-training bilateral intra-hippocampal infusion of 1400W as a selective inducible nitric oxide synthase (iNOS) inhibitor (10, 50, and 100 μM/side), alone and in combination, on the spatial memory retention in Morris water maze (MWM) were investigated. Animals were trained for 4 days and tested 48 h after completion of training. Also, the molecular effects of these compounds on the expression of choline acetyltransferase (ChAT), as a cholinergic marker in the CA1 region of the hippocampus and medial septal area (MSA), were evaluated. Behavioral and molecular findings of this study showed that a 2-week oral administration of zinc chloride (50 mg/kg) impaired spatial memory retention in MWM and decreased ChAT expression. Immunohistochemical analysis of post-training bilateral intra-hippocampal infusion of 1400W revealed a significant increase in ChAT immunoreactivity. Furthermore, post-training bilateral intra-hippocampal infusion of 1400W into the CA1 region of the hippocampus reversed zinc chloride-induced spatial memory impairment in MWM and significantly increased ChAT expression in comparison with zinc chloride-treated animals. Taken together, these results emphasize the role of selective iNOS inhibitors in reversing zinc chloride-induced spatial memory deficits via modulation of cholinergic marker expression.

  16. A rat retinal damage model predicts for potential clinical visual disturbances induced by Hsp90 inhibitors

    SciTech Connect

    Zhou, Dan; Liu, Yuan; Ye, Josephine; Ying, Weiwen; Ogawa, Luisa Shin; Inoue, Takayo; Tatsuta, Noriaki; Wada, Yumiko; Koya, Keizo; Huang, Qin; Bates, Richard C.; Sonderfan, Andrew J.

    2013-12-01

    In human trials certain heat shock protein 90 (Hsp90) inhibitors, including 17-DMAG and NVP-AUY922, have caused visual disorders indicative of retinal dysfunction; others such as 17-AAG and ganetespib have not. To understand these safety profile differences we evaluated histopathological changes and exposure profiles of four Hsp90 inhibitors, with or without clinical reports of adverse ocular effects, using a rat retinal model. Retinal morphology, Hsp70 expression (a surrogate marker of Hsp90 inhibition), apoptotic induction and pharmacokinetic drug exposure analysis were examined in rats treated with the ansamycins 17-DMAG and 17-AAG, or with the second-generation compounds NVP-AUY922 and ganetespib. Both 17-DMAG and NVP-AUY922 induced strong yet restricted retinal Hsp70 up-regulation and promoted marked photoreceptor cell death 24 h after the final dose. In contrast, neither 17-AAG nor ganetespib elicited photoreceptor injury. When the relationship between drug distribution and photoreceptor degeneration was examined, 17-DMAG and NVP-AUY922 showed substantial retinal accumulation, with high retina/plasma (R/P) ratios and slow elimination rates, such that 51% of 17-DMAG and 65% of NVP-AUY922 present at 30 min post-injection were retained in the retina 6 h post-dose. For 17-AAG and ganetespib, retinal elimination was rapid (90% and 70% of drugs eliminated from the retina at 6 h, respectively) which correlated with lower R/P ratios. These findings indicate that prolonged inhibition of Hsp90 activity in the eye results in photoreceptor cell death. Moreover, the results suggest that the retina/plasma exposure ratio and retinal elimination rate profiles of Hsp90 inhibitors, irrespective of their chemical class, may predict for ocular toxicity potential. - Highlights: • In human trials some Hsp90 inhibitors cause visual disorders, others do not. • Prolonged inhibition of Hsp90 in the rat eye results in photoreceptor cell death. • Retina/plasma ratio and retinal

  17. Effect of the Angiotensin I Converting Enzyme Inhibitor, MK-421, on Experimentally Induced Drinking

    NASA Technical Reports Server (NTRS)

    Fregley, Melvin J.; Fater, Dennis C.; Greenleaf, John E.

    1982-01-01

    MK-421, the ethyl ester maleate salt of N-(S)-1-(ethoxycarbonyl)-3-phenyl-propyl- Ala-L-Pro, is an angiotensin I converting enzyme inhibitor. An initial objective was to determine whether MK-421, administered at 0, 2.5, 5.0, 10.0, 20.0 and 40.0 mg/kg, ip to 96 female rats 15 min prior to administration of the beta-adrenergic agonist, isoproterenol (25 microgram/kg, ip), would inhibit the drinking induced by isoproterenol during 2 h after its administration. The water intake induced by isoproterenol was inhibited significantly by 2.5 mg MK-421/kg. When a similar experiment was performed using Angiotensin I (AI) (200 microgram/kg, ip) as the dipsogenic agent, MK-421 (5 mg/kg, ip), administered 15 min prior to AI, inhibited significantly both the dipsogenic and the diuretic effect of AI. However, administration of angiotensin II (AII, 200 microgram/kg, ip) 15 min after MK-421 (5mg/kg) was accompanied by a water intake that did not differ from AII alone. The drink induced by ip administration of 1.0 m NaCl solution (1% of body wt, ip) was not inhibited by administration of MK-421 (5 mg/kg) 15 min prior to allowing access to water while the drink induced by a 24 h dehydration was partially inhibited. Thus, the drinks induced by administraition of either isoproterenol or AI are dependent on formation of AII. That induced by dehydration is partially dependent, while that induced by hypertonic siilinc is independent of the formation of AII.

  18. Pex11a deficiency is associated with a reduced abundance of functional peroxisomes and aggravated renal interstitial lesions.

    PubMed

    Weng, Huachun; Ji, Xu; Endo, Kosuke; Iwai, Naoharu

    2014-11-01

    Although proteinuria is known to be associated with the deterioration of chronic kidney disease, the molecular basis of this mechanism is not fully understood. We previously found that Pex11a deficiency was associated with a reduction of functional peroxisomes and impaired fatty acid metabolism in hepatocytes and resulted in steatosis. Proximal tubule cells are rich in peroxisomes. We assessed whether Pex11a deficiency might result in the derangement of peroxisome systems in proximal tubule cells and the aggravation of tubulointerstitial lesions in chronic kidney disease. Histological analyses showed that the number of functional peroxisomes in proximal tubule cells was reduced in Pex11a knockout (Pex11a(-/-)) mice. To clarify whether a decrease in the number of tubular peroxisomes might aggravate interstitial lesions, we assessed 2 models in which proximal tubule cells are overloaded with fatty acids (ie, deoxycorticosterone acetate and salt hypertension and the overload of fatty acid-bound albumin). Deoxycorticosterone acetate -salt-treated Pex11a(-/-) mice exhibited greater interstitial lesions than deoxycorticosterone acetate-salt-treated wild-type mice in terms of tubular lipid accumulation, blood pressure, urinary albumin, urinary N-acetyl-β-d-glucosaminidase, urinary 8-iso-prostane, and the histological evaluation of fibrosis and inflammation. An overload of fatty acid-bound albumin also resulted in more severe tubulointerstitial lesions in Pex11a(-/-) mice than in wild-type mice. Fenofibrate, a peroxisome proliferator-activated receptor-α agonist, restored the abundance of peroxisomes and reduced the tubulointerstitial lesions induced by deoxycorticosterone acetate-salt hypertension. In conclusion, our results indicate that proximal tubule peroxisomes play an important role in proteinuria-induced interstitial lesions. The activation of tubular peroxisomes might be an excellent therapeutic strategy against chronic kidney disease.

  19. The B-RafV600E inhibitor dabrafenib selectively inhibits RIP3 and alleviates acetaminophen-induced liver injury

    PubMed Central

    Li, J-X; Feng, J-M; Wang, Y; Li, X-H; Chen, X-X; Su, Y; Shen, Y-Y; Chen, Y; Xiong, B; Yang, C-H; Ding, J; Miao, Z-H

    2014-01-01

    Receptor-interacting protein (RIP)3 is a critical regulator of necroptosis and has been demonstrated to be associated with various diseases, suggesting that its inhibitors are promising in the clinic. However, there have been few RIP3 inhibitors reported as yet. B-RafV600E inhibitors are an important anticancer drug class for metastatic melanoma therapy. In this study, we found that 6 B-Raf inhibitors could inhibit RIP3 enzymatic activity in vitro. Among them, dabrafenib showed the most potent inhibition on RIP3, which was achieved by its ATP-competitive binding to the enzyme. Dabrafenib displayed highly selective inhibition on RIP3 over RIP1, RIP2 and RIP5. Moreover, only dabrafenib rescued cells from RIP3-mediated necroptosis induced by the necroptosis-induced combinations, that is, tumor necrosis factor (TNF)α, TNF-related apoptosis-inducing ligand or Fas ligand plus Smac mimetic and the caspase inhibitor z-VAD. Dabrafenib decreased the RIP3-mediated Ser358 phosphorylation of mixed lineage kinase domain-like protein (MLKL) and disrupted the interaction between RIP3 and MLKL. Notably, RIP3 inhibition of dabrafenib appeared to be independent of its B-Raf inhibition. Dabrafenib was further revealed to prevent acetaminophen-induced necrosis in normal human hepatocytes, which is considered to be mediated by RIP3. In acetaminophen-overdosed mouse models, dabrafenib was found to apparently ease the acetaminophen-caused liver damage. The results indicate that the anticancer B-RafV600E inhibitor dabrafenib is a RIP3 inhibitor, which could serve as a sharp tool for probing the RIP3 biology and as a potential preventive or therapeutic agent for RIP3-involved necroptosis-related diseases such as acetaminophen-induced liver damage. PMID:24901049

  20. An inventory of peroxisomal proteins and pathways in Drosophila melanogaster

    PubMed Central

    Faust, Joseph E.; Verma, Avani; Peng, Chengwei; McNew, James A.

    2012-01-01

    Peroxisomes are ubiquitous organelles housing a variety of essential biochemical pathways. Peroxisome dysfunction causes a spectrum of human diseases known as peroxisome biogenesis disorders (PBD). While much is known regarding the mechanism of peroxisome biogenesis, it is still unclear how peroxisome dysfunction leads to the disease state. Several recent studies have shown that mutations in Drosophila peroxin genes cause phenotypes similar to those seen in humans with PBDs suggesting that Drosophila might be a useful system to model PBDs. We have analyzed the proteome of Drosophila to identify the proteins involved in peroxisomal biogenesis and homeostasis as well as metabolic enzymes that function within the organelle. The subcellular localization of five of these predicted peroxisomal proteins was confirmed. Similar to C. elegans, Drosophila appears to only utilize the peroxisome targeting signal (PTS) type 1 system for matrix protein import. This work will further our understanding of peroxisomes in Drosophila and add to the usefulness of this emerging model system. PMID:22758915

  1. IL-21 induces inhibitor of differentiation 2 and leads to complete abrogation of anaphylaxis in mice.

    PubMed

    Kishida, Tsunao; Hiromura, Yayoi; Shin-Ya, Masaharu; Asada, Hidetsugu; Kuriyama, Hiroko; Sugai, Manabu; Shimizu, Akira; Yokota, Yoshifumi; Hama, Takemitsu; Imanishi, Jiro; Hisa, Yasuo; Mazda, Osam

    2007-12-15

    IL-21 exerts pleiotrophic immunomodulatory activities on a variety of target cells including B cells that undergo class switch recombination (CSR) to IgE. In this study, we examined whether IgE-mediated systemic anaphylaxis was controlled by in vivo administration of IL-21 using the peanut allergy model in mice and investigated the molecular mechanisms underlying the IL-21-induced regulation of IgE. The anaphylactic reaction was completely abolished by the administration of recombinant mouse IL-21 or an IL-21 expression plasmid in terms of the change of body temperature and anaphylactic symptoms. The recombinant mouse IL-21 treatment remarkably suppressed IgE CSR in splenic B cells, resulting in significant decrease in serum concentrations of total as well as allergen-specific IgE. In the meanwhile, IL-21 provoked B cells in normal as well as allergic mice to express the inhibitor of differentiation 2 (Id2) gene that was shown to be crucially involved in the regulation of the activation-induced cytidine deaminase and IgE CSR. Moreover, mice genetically deficient for Id2 were completely unsusceptible to IL-21-induced prevention of IgE CSR and anaphylaxis. The present study strongly suggests that IL-21 is capable of regulating systemic allergic reactions by inducing the transcriptional regulator Id2, and the cytokine may be useful for clinical intervention for allergic diseases including anaphylaxis.

  2. Inter-α inhibitor protein and its associated glycosaminoglycans protect against histone-induced injury

    PubMed Central

    Chaaban, Hala; Keshari, Ravi S.; Silasi-Mansat, Robert; Popescu, Narcis I.; Mehta-D’Souza, Padmaja; Lim, Yow-Pin

    2015-01-01

    Extracellular histones are mediators of tissue injury and organ dysfunction; therefore they constitute potential therapeutic targets in sepsis, inflammation, and thrombosis. Histone cytotoxicity in vitro decreases in the presence of plasma. Here, we demonstrate that plasma inter-α inhibitor protein (IAIP) neutralizes the cytotoxic effects of histones and decreases histone-induced platelet aggregation. These effects are mediated through the negatively charged glycosaminoglycans (GAGs) chondroitin sulfate and high-molecular-weight hyaluronan (HMW-HA) associated with IAIP. Cell surface anionic glycosaminoglycans heparan sulfate and HA protect the cells against histone-mediated damage in vitro. Surface plasmon resonance showed that both IAIP and HMW-HA directly bind to recombinant histone H4. In vivo neutralization of histones with IAIP and HMW-HA prevented histone-induced thrombocytopenia, bleeding, and lung microvascular thrombosis, decreased neutrophil activation, and averted histone-induced production of inflammatory cytokines and chemokines. IAIP and HMW-HA colocalized with histones in necrotic tissues and areas that displayed neutrophil extracellular traps. Increasing amounts of IAIP-histone complexes detected in the plasma of septic baboons correlated with increase in histones and/or nucleosomes and consumption of plasma IAIP. Our data suggest that IAIP, chondroitin sulfate, and HMW-HA are potential therapeutic agents to protect against histone-induced cytotoxicity, coagulopathy, systemic inflammation, and organ damage during inflammatory conditions such as sepsis and trauma. PMID:25631771

  3. [Cell senescence induced by histone deacetylase inhibitor sodium butyrate in rodent transformed cells resistant to apoptosis].

    PubMed

    Shitikova, Zh V; Aksenov, N D; Pospelov, V A; Pospelov, T V

    2011-01-01

    The capacity of HDAC inhibitor sodium butyrate to induce senescence in cells derived from rat embryonic fibroblasts transformed by E1A+E1B19 kDa oncogenes has been studied. These transformants are resistant to apoptosis in response to gamma-irradiation and growth factor deprivation. The process of cell senescence was investigated by the analysis of cell growth curves, G1/S and G2/M cell cycle arrest, and senescent associated beta-galactosidase expression. The irreversibility of sodium butyrate antiproliferative activity was analyzed by clonogenic assay. We show that sodium butyrate suppresses proliferation and induces senescence in the E1A+E1B19 kDa transformed cells. Interestingly, NaB induces growth arrest due to accumulation of cells in G2/M phase, these cells are not tetraploid but mainly binuclear. Thus, in case of NaB induced senescence in E1A+E1B19 kDa transformed fibroblasts, the observed suppression of cell proliferation may be the result of cytokinesis failure leading to formation of binuclear and multinuclear cells incapable to proliferate.

  4. Inter-α inhibitor protein and its associated glycosaminoglycans protect against histone-induced injury.

    PubMed

    Chaaban, Hala; Keshari, Ravi S; Silasi-Mansat, Robert; Popescu, Narcis I; Mehta-D'Souza, Padmaja; Lim, Yow-Pin; Lupu, Florea

    2015-04-01

    Extracellular histones are mediators of tissue injury and organ dysfunction; therefore they constitute potential therapeutic targets in sepsis, inflammation, and thrombosis. Histone cytotoxicity in vitro decreases in the presence of plasma. Here, we demonstrate that plasma inter-α inhibitor protein (IAIP) neutralizes the cytotoxic effects of histones and decreases histone-induced platelet aggregation. These effects are mediated through the negatively charged glycosaminoglycans (GAGs) chondroitin sulfate and high-molecular-weight hyaluronan (HMW-HA) associated with IAIP. Cell surface anionic glycosaminoglycans heparan sulfate and HA protect the cells against histone-mediated damage in vitro. Surface plasmon resonance showed that both IAIP and HMW-HA directly bind to recombinant histone H4. In vivo neutralization of histones with IAIP and HMW-HA prevented histone-induced thrombocytopenia, bleeding, and lung microvascular thrombosis, decreased neutrophil activation, and averted histone-induced production of inflammatory cytokines and chemokines. IAIP and HMW-HA colocalized with histones in necrotic tissues and areas that displayed neutrophil extracellular traps. Increasing amounts of IAIP-histone complexes detected in the plasma of septic baboons correlated with increase in histones and/or nucleosomes and consumption of plasma IAIP. Our data suggest that IAIP, chondroitin sulfate, and HMW-HA are potential therapeutic agents to protect against histone-induced cytotoxicity, coagulopathy, systemic inflammation, and organ damage during inflammatory conditions such as sepsis and trauma.

  5. Treatment with the hyaluronic Acid synthesis inhibitor 4-methylumbelliferone suppresses LPS-induced lung inflammation.

    PubMed

    McKallip, Robert J; Ban, Hao; Uchakina, Olga N

    2015-01-01

    Exposure to bacterial endotoxins, such as lipopolysaccharide (LPS), can lead to the induction of acute lung injury/acute respiratory distress syndrome (ALI/ARDS). To date, there are no known effective treatments for LPS-induced inflammation. In the current study, we investigated the potential use of the hyaluronic acid (HA) synthesis inhibitor 4-methylumbelliferone (4-MU) on LPS-induced acute lung inflammation. Culturing LPS-activated immune cells with 4-MU led to reduced proliferation, reduced cytokine production, and an increase in apoptosis when compared to untreated cells. Treatment of mice with 4-MU led to protection from LPS-induced lung injury. Specifically, 4-MU treatment led to a reduction in LPS-induced hyaluronic acid synthase (HAS) messenger RNA (mRNA) levels, reduction in lung permeability, and reduction in proinflammatory cytokine production. Taken together, these results suggest that use of 4-MU to target HA production may be an effective treatment for the inflammatory response following exposure to LPS.

  6. Calcineurin inhibitors cyclosporine A and tacrolimus induce vascular inflammation and endothelial activation through TLR4 signaling

    PubMed Central

    Rodrigues-Diez, Raquel; González-Guerrero, Cristian; Ocaña-Salceda, Carlos; Rodrigues-Diez, Raúl R.; Egido, Jesús; Ortiz, Alberto; Ruiz-Ortega, Marta; Ramos, Adrián M.

    2016-01-01

    The introduction of the calcineurin inhibitors (CNIs) cyclosporine and tacrolimus greatly reduced the rate of allograft rejection, although their chronic use is marred by a range of side effects, among them vascular toxicity. In transplant patients, it is proved that innate immunity promotes vascular injury triggered by ischemia-reperfusion damage, atherosclerosis and hypertension. We hypothesized that activation of the innate immunity and inflammation may contribute to CNI toxicity, therefore we investigated whether TLR4 mediates toxic responses of CNIs in the vasculature. Cyclosporine and tacrolimus increased the production of proinflammatory cytokines and endothelial activation markers in cultured murine endothelial and vascular smooth muscle cells as well as in ex vivo cultures of murine aortas. CNI-induced proinflammatory events were prevented by pharmacological inhibition of TLR4. Moreover, CNIs were unable to induce inflammation and endothelial activation in aortas from TLR4−/− mice. CNI-induced cytokine and adhesion molecules synthesis in endothelial cells occurred even in the absence of calcineurin, although its expression was required for maximal effect through upregulation of TLR4 signaling. CNI-induced TLR4 activity increased O2−/ROS production and NF-κB-regulated synthesis of proinflammatory factors in cultured as well as aortic endothelial and VSMCs. These data provide new insight into the mechanisms associated with CNI vascular inflammation. PMID:27295076

  7. Dynein light chain interaction with the peroxisomal import docking complex modulates peroxisome biogenesis in yeast.

    PubMed

    Chang, Jinlan; Tower, Robert J; Lancaster, David L; Rachubinski, Richard A

    2013-10-15

    Dynein is a large macromolecular motor complex that moves cargo along microtubules. A motor-independent role for the light chain of dynein, Dyn2p, in peroxisome biology in Saccharomyces cerevisiae was suggested from its interaction with Pex14p, a component of the peroxisomal matrix protein import docking complex. Here we show that cells of the yeast Yarrowia lipolytica deleted for the gene encoding the homologue of Dyn2p are impaired in peroxisome function and biogenesis. These cells exhibit compromised growth on medium containing oleic acid as the carbon source, the metabolism of which requires functional peroxisomes. Their peroxisomes have abnormal morphology, atypical matrix protein localization, and an absence of proteolytic processing of the matrix enzyme thiolase, which normally occurs upon its import into the peroxisome. We also show physical and genetic interactions between Dyn2p and members of the docking complex, particularly Pex17p. Together, our results demonstrate a role for Dyn2p in the assembly of functional peroxisomes and provide evidence that Dyn2p acts in cooperation with the peroxisomal matrix protein import docking complex to effect optimal matrix protein import.

  8. B-Raf inhibitors induce epithelial differentiation in BRAF-mutant colorectal cancer cells.

    PubMed

    Herr, Ricarda; Köhler, Martin; Andrlová, Hana; Weinberg, Florian; Möller, Yvonne; Halbach, Sebastian; Lutz, Lisa; Mastroianni, Justin; Klose, Martin; Bittermann, Nicola; Kowar, Silke; Zeiser, Robert; Olayioye, Monilola A; Lassmann, Silke; Busch, Hauke; Boerries, Melanie; Brummer, Tilman

    2015-01-01

    BRAF mutations are associated with aggressive, less-differentiated and therapy-resistant colorectal carcinoma. However, the underlying mechanisms for these correlations remain unknown. To understand how oncogenic B-Raf contributes to carcinogenesis, in particular to aspects other than cellular proliferation and survival, we generated three isogenic human colorectal carcinoma cell line models in which we can dynamically modulate the expression of the B-Raf(V600E) oncoprotein. Doxycyclin-inducible knockdown of endogenous B-Raf(V600E) decreases cellular motility and invasion in conventional and three-dimensional (3D) culture, whereas it promotes cell-cell contacts and induces various hallmarks of differentiated epithelia. Importantly, all these effects are recapitulated by B-Raf (PLX4720, vemurafenib, and dabrafenib) or MEK inhibitors (trametinib). Surprisingly, loss of B-Raf(V600E) in HT29 xenografts does not only stall tumor growth, but also induces glandular structures with marked expression of CDX2, a tumor-suppressor and master transcription factor of intestinal differentiation. By performing the first transcriptome profiles of PLX4720-treated 3D cultures of HT29 and Colo-205 cells, we identify several upregulated genes linked to epithelial differentiation and effector functions, such as claudin-1, a Cdx-2 target gene encoding a critical tight junction component. Thereby, we provide a mechanism for the clinically observed correlation between mutant BRAF and the loss of Cdx-2 and claudin-1. PLX4720 also suppressed several metastasis-associated transcripts that have not been implicated as targets, effectors or potential biomarkers of oncogenic B-Raf signaling so far. Together, we identify a novel facet of clinically applied B-Raf or MEK inhibitors by showing that they promote cellular adhesion and differentiation of colorectal carcinoma cells. PMID:25381152

  9. Arabidopsis PEROXIN11c-e, FISSION1b, and DYNAMIN-RELATED PROTEIN3A Cooperate in Cell Cycle–Associated Replication of Peroxisomes[W

    PubMed Central

    Lingard, Matthew J.; Gidda, Satinder K.; Bingham, Scott; Rothstein, Steven J.; Mullen, Robert T.; Trelease, Richard N.

    2008-01-01

    Although participation of PEROXIN11 (PEX11), FISSION1 (FISl), and DYNAMIN-RELATED PROTEIN (DRP) has been well established during induced peroxisome proliferation in response to external stimuli, their roles in cell cycle–associated constitutive replication/duplication have not been fully explored. Herein, bimolecular fluorescence complementation experiments with Arabidopsis thaliana suspension cells revealed homooligomerization of all five PEX11 isoforms (PEX11a-e) and heterooligomerizations of all five PEX11 isoforms with FIS1b, but not FIS1a nor DRP3A. Intracellular protein targeting experiments demonstrated that FIS1b, but not FIS1a nor DRP3A, targeted to peroxisomes only when coexpressed with PEX11d or PEX11e. Simultaneous silencing of PEX11c-e or individual silencing of DRP3A, but not FIS1a nor FIS1b, resulted in ∼40% reductions in peroxisome number. During G2 in synchronized cell cultures, peroxisomes sequentially enlarged, elongated, and then doubled in number, which correlated with peaks in PEX11, FIS1, and DRP3A expression. Overall, these data support a model for the replication of preexisting peroxisomes wherein PEX11c, PEX11d, and PEX11e act cooperatively during G2 to promote peroxisome elongation and recruitment of FIS1b to the peroxisome membrane, where DRP3A stimulates fission of elongated peroxisomes into daughter peroxisomes, which are then distributed between daughter cells. PMID:18539750

  10. Arabidopsis PEROXIN11c-e, FISSION1b, and DYNAMIN-RELATED PROTEIN3A cooperate in cell cycle-associated replication of peroxisomes.

    PubMed

    Lingard, Matthew J; Gidda, Satinder K; Bingham, Scott; Rothstein, Steven J; Mullen, Robert T; Trelease, Richard N

    2008-06-01

    Although participation of PEROXIN11 (PEX11), FISSION1 (FISl), and DYNAMIN-RELATED PROTEIN (DRP) has been well established during induced peroxisome proliferation in response to external stimuli, their roles in cell cycle-associated constitutive replication/duplication have not been fully explored. Herein, bimolecular fluorescence complementation experiments with Arabidopsis thaliana suspension cells revealed homooligomerization of all five PEX11 isoforms (PEX11a-e) and heterooligomerizations of all five PEX11 isoforms with FIS1b, but not FIS1a nor DRP3A. Intracellular protein targeting experiments demonstrated that FIS1b, but not FIS1a nor DRP3A, targeted to peroxisomes only when coexpressed with PEX11d or PEX11e. Simultaneous silencing of PEX11c-e or individual silencing of DRP3A, but not FIS1a nor FIS1b, resulted in approximately 40% reductions in peroxisome number. During G2 in synchronized cell cultures, peroxisomes sequentially enlarged, elongated, and then doubled in number, which correlated with peaks in PEX11, FIS1, and DRP3A expression. Overall, these data support a model for the replication of preexisting peroxisomes wherein PEX11c, PEX11d, and PEX11e act cooperatively during G2 to promote peroxisome elongation and recruitment of FIS1b to the peroxisome membrane, where DRP3A stimulates fission of elongated peroxisomes into daughter peroxisomes, which are then distributed between daughter cells.

  11. Differential effects of histone deacetylase inhibitors on phorbol ester- and TGF-beta1 induced murine tissue inhibitor of metalloproteinases-1 gene expression.

    PubMed

    Young, David A; Billingham, Olivia; Sampieri, Clara L; Edwards, Dylan R; Clark, Ian M

    2005-04-01

    Expression of the tissue inhibitor of metalloproteinases-1 (Timp-1) gene can be induced by either phorbol myristate acetate (PMA) or transforming growth factor beta1 (TGF-beta1), although the signalling pathways involved are not clearly defined. Canonically, histone deacetylase inhibitors (HDACi) such as trichostatin A (TSA) or sodium butyrate (NaB) increase total cellular histone acetylation and activate expression of susceptible genes. Remarkably, PMA and TGF-beta1 stimulation of Timp-1 show a differential response to TSA or NaB. TSA or NaB potentiate PMA-induced Timp-1 expression but repress TGF-beta1-induced Timp-1 expression. The repression of TGF-beta1-induced Timp-1 by TSA was maximal at 5 ng.mL(-1), while for the superinduction of PMA-induced Timp-1 expression, the maximal dose is > 500 ng x mL(-1) TSA. A further HDACi, valproic acid, did not block TGF-beta1-induced Timp-1 expression, demonstrating that different HDACs impact on the induction of Timp-1. For either PMA or TGF-beta1 to induce Timp-1 expression, new protein synthesis is required, and the induction of AP-1 factors closely precedes that of Timp-1. The effects of the HDACi can be reiterated in transient transfection using Timp-1 promoter constructs. Mutation or deletion of the AP-1 motif (-59/-53) in the Timp-1 promoter diminishes PMA-induction of reporter constructs, however, the further addition of TSA still superinduces the reporter. In c-Jun-/- cells, PMA still stimulates Timp-1 expression, but TSA superinduction is lost. Transfection of a series of Timp-1 promoter constructs identified three regions through which TSA superinduces PMA-induced Timp-1 and we have demonstrated specific protein binding to two of these regions which contain either an avian erythroblastosis virus E26 (v-ets) oncogene homologue (Ets) or Sp1 binding motif.

  12. Inhibition of chlorine-induced lung injury by the type 4 phosphodiesterase inhibitor rolipram

    SciTech Connect

    Chang, Weiyuan; Chen, Jing; Schlueter, Connie F.; Rando, Roy J.; Pathak, Yashwant V.; Hoyle, Gary W.

    2012-09-01

    Chlorine is a highly toxic respiratory irritant that when inhaled causes epithelial cell injury, alveolar-capillary barrier disruption, airway hyperreactivity, inflammation, and pulmonary edema. Chlorine is considered a chemical threat agent, and its release through accidental or intentional means has the potential to result in mass casualties from acute lung injury. The type 4 phosphodiesterase inhibitor rolipram was investigated as a rescue treatment for chlorine-induced lung injury. Rolipram inhibits degradation of the intracellular signaling molecule cyclic AMP. Potential beneficial effects of increased cyclic AMP levels include inhibition of pulmonary edema, inflammation, and airway hyperreactivity. Mice were exposed to chlorine (whole body exposure, 228–270 ppm for 1 h) and were treated with rolipram by intraperitoneal, intranasal, or intramuscular (either aqueous or nanoemulsion formulation) delivery starting 1 h after exposure. Rolipram administered intraperitoneally or intranasally inhibited chlorine-induced pulmonary edema. Minor or no effects were observed on lavage fluid IgM (indicative of plasma protein leakage), KC (Cxcl1, neutrophil chemoattractant), and neutrophils. All routes of administration inhibited chlorine-induced airway hyperreactivity assessed 1 day after exposure. The results of the study suggest that rolipram may be an effective rescue treatment for chlorine-induced lung injury and that both systemic and targeted administration to the respiratory tract were effective routes of delivery. -- Highlights: ► Chlorine causes lung injury when inhaled and is considered a chemical threat agent. ► Rolipram inhibited chlorine-induced pulmonary edema and airway hyperreactivity. ► Post-exposure rolipram treatments by both systemic and local delivery were effective. ► Rolipram shows promise as a rescue treatment for chlorine-induced lung injury.

  13. Redox interplay between mitochondria and peroxisomes

    PubMed Central

    Lismont, Celien; Nordgren, Marcus; Van Veldhoven, Paul P.; Fransen, Marc

    2015-01-01

    Reduction-oxidation or “redox” reactions are an integral part of a broad range of cellular processes such as gene expression, energy metabolism, protein import and folding, and autophagy. As many of these processes are intimately linked with cell fate decisions, transient or chronic changes in cellular redox equilibrium are likely to contribute to the initiation and progression of a plethora of human diseases. Since a long time, it is known that mitochondria are major players in redox regulation and signaling. More recently, it has become clear that also peroxisomes have the capacity to impact redox-linked physiological processes. To serve this function, peroxisomes cooperate with other organelles, including mitochondria. This review provides a comprehensive picture of what is currently known about the redox interplay between mitochondria and peroxisomes in mammals. We first outline the pro- and antioxidant systems of both organelles and how they may function as redox signaling nodes. Next, we critically review and discuss emerging evidence that peroxisomes and mitochondria share an intricate redox-sensitive relationship and cooperate in cell fate decisions. Key issues include possible physiological roles, messengers, and mechanisms. We also provide examples of how data mining of publicly-available datasets from “omics” technologies can be a powerful means to gain additional insights into potential redox signaling pathways between peroxisomes and mitochondria. Finally, we highlight the need for more studies that seek to clarify the mechanisms of how mitochondria may act as dynamic receivers, integrators, and transmitters of peroxisome-derived mediators of oxidative stress. The outcome of such studies may open up exciting new avenues for the community of researchers working on cellular responses to organelle-derived oxidative stress, a research field in which the role of peroxisomes is currently highly underestimated and an issue of discussion. PMID:26075204

  14. The effects of celecoxib, a COX-2 selective inhibitor, on acute inflammation induced in irradiated rats.

    PubMed

    Khayyal, M T; El-Ghazaly, Mona A; El-Hazek, R M; Nada, A S

    2009-10-01

    The potential value of selective and non-selective COX-2 inhibitors in preventing some of the biochemical changes induced by ionizing radiation was studied in rats exposed to carrageenan-induced paw edema and 6-day-old air pouch models. The animals were exposed to different exposure levels of gamma-radiation, namely either to single doses of 2 and 7.5 Gy or a fractionated dose level of 7.5 Gy delivered as 0.5 Gy twice weekly for 7.5 weeks. The inflammatory response produced by carrageenan in irradiated rats was markedly higher than that induced in non-irradiated animals, and depended on the extent of irradiation. Celecoxib, a selective COX-2 inhibitor, in doses of 3, 5, 10, and 15 mg/kg was effective in reducing paw edema in irradiated and non-irradiated rats in a dose-dependent manner as well as diclofenac (3 mg/kg), a non-selective COX inhibitor. Irradiation of animals before the induction of the air pouch by an acute dose of 2 Gy led to a significant increase in leukocytic count, as well as in the level of interleukin-6 (IL-6), interleukin-1beta (IL-1beta), tumor necrosis factor-alpha (TNF-alpha), LTB(4), PGE(2) (as an index of COX-2 activity), TXB(2) (as an index of COX-1 activity), and the plasma level of MDA. This increase in level of these parameters was more marked than that observed in the non-irradiated animals subjected to the inflammagen. The blood GSH level was not affected by the dose of irradiation used, whereas superoxide dismutase (SOD) activity was suppressed. In many respects, celecoxib (5 mg/kg) was as potent as diclofenac in decreasing the elevated levels of IL-6, IL-1beta, TNF-alpha, LTB(4), PGE(2), but lacked any significant effect on TXB(2) level. Since it is mostly selective for COX-2 with a rare effect on COX-1 enzyme, both drugs at the selected dose levels showed no effect on level of MDA, GSH, and SOD activity.

  15. Immune checkpoint inhibitors enhance cytotoxicity of cytokine-induced killer cells against human myeloid leukaemic blasts.

    PubMed

    Poh, Su Li; Linn, Yeh Ching

    2016-05-01

    We studied whether blockade of inhibitory receptors on cytokine-induced killer (CIK) cells by immune checkpoint inhibitors could increase its anti-tumour potency against haematological malignancies. CIK cultures were generated from seven normal donors and nine patients with acute myeloid leukaemia (AML), acute lymphoblastic leukaemia (ALL) or multiple myeloma (MM). The inhibitory receptors B and T lymphocyte attenuator, CD200 receptor, lymphocyte activation gene-3 (LAG-3) and T cell immunoglobulin and mucin-domain-containing-3 (TIM-3) were present at variable percentages in most CIK cultures, while cytotoxic T lymphocyte-associated protein 4 (CTLA-4), programmed death-1 (PD-1) and killer cell immunoglobulin-like receptors (KIR2DL1/2/3) were expressed at low level in most cultures. Without blockade, myeloid leukaemia cells were susceptible to autologous and allogeneic CIK-mediated cytotoxicity. Blockade of KIR, LAG-3, PD-1 and TIM-3 but not CTLA-4 resulted in remarkable increase in killing against these targets, even in those with poor baseline cytotoxicity. ALL and MM targets were resistant to CIK-mediated cytotoxicity, and blockade of receptors did not increase cytotoxicity to a meaningful extent. Combination of inhibitors against two receptors did not further increase cytotoxicity. Interestingly, potentiation of CIK killing by blocking antibodies was not predicted by expression of receptors on CIK and their respective ligands on the targets. Compared to un-activated T and NK cells, blockade potentiated the cytotoxicity of CIK cells to a greater degree and at a lower E:T ratio, but without significant increase in cytotoxicity against normal white cell. Our findings provide the basis for clinical trial combining autologous CIK cells with checkpoint inhibitors for patients with AML.

  16. Roles of Peroxisomes in the Rice Blast Fungus

    PubMed Central

    Liu, Caiyun

    2016-01-01

    The rice blast fungus, Magnaporthe oryzae, is a model plant pathogenic fungus and is a severe threat to global rice production. Over the past two decades, it has been found that the peroxisomes play indispensable roles during M. oryzae infection. Given the importance of the peroxisomes for virulence, we review recent advances of the peroxisomes roles during M. oryzae infection processes. We firstly introduce the molecular mechanisms and life cycles of the peroxisomes. And then, metabolic functions related to the peroxisomes are also discussed. Finally, we provide an overview of the relationship between peroxisomes and pathogenicity. PMID:27610388

  17. Roles of Peroxisomes in the Rice Blast Fungus

    PubMed Central

    Liu, Caiyun

    2016-01-01

    The rice blast fungus, Magnaporthe oryzae, is a model plant pathogenic fungus and is a severe threat to global rice production. Over the past two decades, it has been found that the peroxisomes play indispensable roles during M. oryzae infection. Given the importance of the peroxisomes for virulence, we review recent advances of the peroxisomes roles during M. oryzae infection processes. We firstly introduce the molecular mechanisms and life cycles of the peroxisomes. And then, metabolic functions related to the peroxisomes are also discussed. Finally, we provide an overview of the relationship between peroxisomes and pathogenicity.

  18. Roles of Peroxisomes in the Rice Blast Fungus.

    PubMed

    Chen, Xiao-Lin; Wang, Zhao; Liu, Caiyun

    2016-01-01

    The rice blast fungus, Magnaporthe oryzae, is a model plant pathogenic fungus and is a severe threat to global rice production. Over the past two decades, it has been found that the peroxisomes play indispensable roles during M. oryzae infection. Given the importance of the peroxisomes for virulence, we review recent advances of the peroxisomes roles during M. oryzae infection processes. We firstly introduce the molecular mechanisms and life cycles of the peroxisomes. And then, metabolic functions related to the peroxisomes are also discussed. Finally, we provide an overview of the relationship between peroxisomes and pathogenicity. PMID:27610388

  19. Proteome analysis of peroxisomes from etiolated Arabidopsis seedlings identifies a peroxisomal protease involved in β-oxidation and development.

    PubMed

    Quan, Sheng; Yang, Pingfang; Cassin-Ross, Gaëlle; Kaur, Navneet; Switzenberg, Robert; Aung, Kyaw; Li, Jiying; Hu, Jianping

    2013-12-01

    Plant peroxisomes are highly dynamic organelles that mediate a suite of metabolic processes crucial to development. Peroxisomes in seeds/dark-grown seedlings and in photosynthetic tissues constitute two major subtypes of plant peroxisomes, which had been postulated to contain distinct primary biochemical properties. Multiple in-depth proteomic analyses had been performed on leaf peroxisomes, yet the major makeup of peroxisomes in seeds or dark-grown seedlings remained unclear. To compare the metabolic pathways of the two dominant plant peroxisomal subtypes and discover new peroxisomal proteins that function specifically during seed germination, we performed proteomic analysis of peroxisomes from etiolated Arabidopsis (Arabidopsis thaliana) seedlings. The detection of 77 peroxisomal proteins allowed us to perform comparative analysis with the peroxisomal proteome of green leaves, which revealed a large overlap between these two primary peroxisomal variants. Subcellular targeting analysis by fluorescence microscopy validated around 10 new peroxisomal proteins in Arabidopsis. Mutant analysis suggested the role of the cysteine protease RESPONSE TO DROUGHT21A-LIKE1 in β-oxidation, seed germination, and growth. This work provides a much-needed road map of a major type of plant peroxisome and has established a basis for future investigations of peroxisomal proteolytic processes to understand their roles in development and in plant interaction with the environment.

  20. Interaction of peroxisomes with microtubules. In vitro studies using a novel peroxisome-microtubule binding assay.

    PubMed

    Thiemann, M; Schrader, M; Völkl, A; Baumgart, E; Fahimi, H D

    2000-10-01

    The association of membrane-bounded cell organelles to microtubules is crucial for determination of their shape, intracellular localization and translocation. We have shown previously the high affinity binding of peroxisomes to microtubules which appears to be of static nature as in vivo studies indicate that only a few peroxisomes move along the microtubular tracks. In order to characterize the interactions of peroxisomes with microtubules, we have developed a semiquantitative in vitro binding assay, which is based on the association of highly purified rat liver peroxisomes to microtubules coated onto microtiterplates. The binding was visualized by differential interference contrast and immunofluorescence using a confocal laser scanning microscope. The binding was concentration dependent and saturable, being affected by time, temperature, and pH. Addition of ATP or the motor proteins kinesin and dynein increased the binding capacity, while ATP-depletion or microtubule associated proteins (MAPs) decreased it. KCl treatment of peroxisomes reduced the binding, which was restored by dialyzed KCl-stripping eluate as well as by rat liver cytosol. The reconstituting effect of cytosol was abolished by its pretreatment with proteases or N-ethylmaleimide. Moreover, the treatment of peroxisomes with proteases or N-ethylmaleimide reduced their binding, which was not reversed by cytosol. These results suggest the involvement of a peroxisomal membrane protein and cytosolic factor(s) in the binding of peroxisomes to microtubules. This notion is supported by the observation that distinct subfractions of dialyzed KCl-stripping eluate obtained by gel chromatography augmented the binding. Those subfractions, as well as purified peroxisome fractions, exhibited strong immunoreactivity with an antibody to cytoplasmic linker protein (CLIP)-115, revealing a 70-kDa polypeptide. Moreover, immunodepletion of KCl-stripping eluate and its subfractions with an antibody to the conserved

  1. Amelioration of Acute Kidney Injury in Lipopolysaccharide-Induced Systemic Inflammatory Response Syndrome by an Aldose Reductase Inhibitor, Fidarestat

    PubMed Central

    Takahashi, Kazunori; Mizukami, Hiroki; Kamata, Kosuke; Inaba, Wataru; Kato, Noriaki; Hibi, Chihiro; Yagihashi, Soroku

    2012-01-01

    Background Systemic inflammatory response syndrome is a fatal disease because of multiple organ failure. Acute kidney injury is a serious complication of systemic inflammatory response syndrome and its genesis is still unclear posing a difficulty for an effective treatment. Aldose reductase (AR) inhibitor is recently found to suppress lipopolysaccharide (LPS)-induced cardiac failure and its lethality. We studied the effects of AR inhibitor on LPS-induced acute kidney injury and its mechanism. Methods Mice were injected with LPS and the effects of AR inhibitor (Fidarestat 32 mg/kg) before or after LPS injection were examined for the mortality, severity of renal failure and kidney pathology. Serum concentrations of cytokines (interleukin-1β, interleukin-6, monocyte chemotactic protein-1 and tumor necrosis factor-α) and their mRNA expressions in the lung, liver, spleen and kidney were measured. We also evaluated polyol metabolites in the kidney. Results Mortality rate within 72 hours was significantly less in LPS-injected mice treated with AR inhibitor both before (29%) and after LPS injection (40%) than untreated mice (90%). LPS-injected mice showed marked increases in blood urea nitrogen, creatinine and cytokines, and AR inhibitor treatment suppressed the changes. LPS-induced acute kidney injury was associated with vacuolar degeneration and apoptosis of renal tubular cells as well as infiltration of neutrophils and macrophages. With improvement of such pathological findings, AR inhibitor treatment suppressed the elevation of cytokine mRNA levels in multiple organs and renal sorbitol accumulation. Conclusion AR inhibitor treatment ameliorated LPS-induced acute kidney injury, resulting in the lowered mortality. PMID:22253906

  2. Hesperetin, a Selective Phosphodiesterase 4 Inhibitor, Effectively Suppresses Ovalbumin-Induced Airway Hyperresponsiveness without Influencing Xylazine/Ketamine-Induced Anesthesia.

    PubMed

    Shih, Chung-Hung; Lin, Ling-Hung; Hsu, Hsin-Te; Wang, Kuo-Hsien; Lai, Chi-Yin; Chen, Chien-Ming; Ko, Wun-Chang

    2012-01-01

    Hesperetin, a selective phosphodiesterase (PDE)4 inhibitor, is present in the traditional Chinese medicine, "Chen Pi." Therefore, we were interested in investigating its effects on ovalbumin- (OVA-) induced airway hyperresponsiveness, and clarifying its rationale for ameliorating asthma and chronic obstructive pulmonary disease (COPD). Hesperetin was revealed to have a therapeutic (PDE4(H)/PDE4(L)) ratio of >11. Hesperetin (10 ~ 30 μmol/kg, intraperitoneally (i.p.)) dose-dependently and significantly attenuated the airway hyperresponsiveness induced by methacholine. It also significantly suppressed the increases in total inflammatory cells, macrophages, lymphocytes, neutrophils, and eosinophils, and levels of cytokines, including interleukin (IL)-2, IL-4, IL-5, interferon-γ, and tumor necrosis factor-α in bronchoalveolar lavage fluid (BALF). It dose-dependently and significantly suppressed total and OVA-specific immunoglobulin E levels in the BALF and serum. However, hesperetin did not influence xylazine/ketamine-induced anesthesia, suggesting that hesperetin has few or no emetic effects. In conclusion, the rationales for ameliorating allergic asthma and COPD by hesperetin are anti-inflammation, immunoregulation, and bronchodilation.

  3. Hesperetin, a Selective Phosphodiesterase 4 Inhibitor, Effectively Suppresses Ovalbumin-Induced Airway Hyperresponsiveness without Influencing Xylazine/Ketamine-Induced Anesthesia.

    PubMed

    Shih, Chung-Hung; Lin, Ling-Hung; Hsu, Hsin-Te; Wang, Kuo-Hsien; Lai, Chi-Yin; Chen, Chien-Ming; Ko, Wun-Chang

    2012-01-01

    Hesperetin, a selective phosphodiesterase (PDE)4 inhibitor, is present in the traditional Chinese medicine, "Chen Pi." Therefore, we were interested in investigating its effects on ovalbumin- (OVA-) induced airway hyperresponsiveness, and clarifying its rationale for ameliorating asthma and chronic obstructive pulmonary disease (COPD). Hesperetin was revealed to have a therapeutic (PDE4(H)/PDE4(L)) ratio of >11. Hesperetin (10 ~ 30 μmol/kg, intraperitoneally (i.p.)) dose-dependently and significantly attenuated the airway hyperresponsiveness induced by methacholine. It also significantly suppressed the increases in total inflammatory cells, macrophages, lymphocytes, neutrophils, and eosinophils, and levels of cytokines, including interleukin (IL)-2, IL-4, IL-5, interferon-γ, and tumor necrosis factor-α in bronchoalveolar lavage fluid (BALF). It dose-dependently and significantly suppressed total and OVA-specific immunoglobulin E levels in the BALF and serum. However, hesperetin did not influence xylazine/ketamine-induced anesthesia, suggesting that hesperetin has few or no emetic effects. In conclusion, the rationales for ameliorating allergic asthma and COPD by hesperetin are anti-inflammation, immunoregulation, and bronchodilation. PMID:22454667

  4. PredPlantPTS1: A Web Server for the Prediction of Plant Peroxisomal Proteins.

    PubMed

    Reumann, Sigrun; Buchwald, Daniela; Lingner, Thomas

    2012-01-01

    Prediction of subcellular protein localization is essential to correctly assign unknown proteins to cell organelle-specific protein networks and to ultimately determine protein function. For metazoa, several computational approaches have been developed in the past decade to predict peroxisomal proteins carrying the peroxisome targeting signal type 1 (PTS1). However, plant-specific PTS1 protein prediction methods have been lacking up to now, and pre-existing methods generally were incapable of correctly predicting low-abundance plant proteins possessing non-canonical PTS1 patterns. Recently, we presented a machine learning approach that is able to predict PTS1 proteins for higher plants (spermatophytes) with high accuracy and which can correctly identify unknown targeting patterns, i.e., novel PTS1 tripeptides and tripeptide residues. Here we describe the first plant-specific web server PredPlantPTS1 for the prediction of plant PTS1 proteins using the above-mentioned underlying models. The server allows the submission of protein sequences from diverse spermatophytes and also performs well for mosses and algae. The easy-to-use web interface provides detailed output in terms of (i) the peroxisomal targeting probability of the given sequence, (ii) information whether a particular non-canonical PTS1 tripeptide has already been experimentally verified, and (iii) the prediction scores for the single C-terminal 14 amino acid residues. The latter allows identification of predicted residues that inhibit peroxisome targeting and which can be optimized using site-directed mutagenesis to raise the peroxisome targeting efficiency. The prediction server will be instrumental in identifying low-abundance and stress-inducible peroxisomal proteins and defining the entire peroxisomal proteome of Arabidopsis and agronomically important crop plants. PredPlantPTS1 is freely accessible at ppp.gobics.de.

  5. The Cytoskeleton and the Peroxisomal-Targeted SNOWY COTYLEDON3 Protein Are Required for Chloroplast Development in Arabidopsis[W

    PubMed Central

    Albrecht, Verónica; Šimková, Klára; Carrie, Chris; Delannoy, Etienne; Giraud, Estelle; Whelan, Jim; Small, Ian David; Apel, Klaus; Badger, Murray R.; Pogson, Barry James

    2010-01-01

    Here, we describe the snowy cotyledon3 (sco3-1) mutation, which impairs chloroplast and etioplast development in Arabidopsis thaliana seedlings. SCO3 is a member of a largely uncharacterized protein family unique to the plant kingdom. The sco3-1 mutation alters chloroplast morphology and development, reduces chlorophyll accumulation, impairs thylakoid formation and photosynthesis in seedlings, and results in photoinhibition under extreme CO2 concentrations in mature leaves. There are no readily apparent changes to chloroplast biology, such as transcription or assembly that explain the disruption to chloroplast biogenesis. Indeed, SCO3 is actually targeted to another organelle, specifically to the periphery of peroxisomes. However, impaired chloroplast development cannot be attributed to perturbed peroxisomal metabolic processes involving germination, fatty acid β-oxidation or photorespiration, though there are so far undescribed changes in low and high CO2 sensitivity in seedlings and young true leaves. Many of the chloroplasts are bilobed, and some have persistent membranous extensions that encircle other cellular components. Significantly, there are changes to the cytoskeleton in sco3-1, and microtubule inhibitors have similar effects on chloroplast biogenesis as sco3-1 does. The localization of SCO3 to the periphery of the peroxisomes was shown to be dependent on a functional microtubule cytoskeleton. Therefore, the microtubule and peroxisome-associated SCO3 protein is required for chloroplast development, and sco3-1, along with microtubule inhibitors, demonstrates an unexpected role for the cytoskeleton and peroxisomes in chloroplast biogenesis. PMID:20978221

  6. Hepatic zonation of the induction of cytochrome P450 IVA, peroxisomal lipid beta-oxidation enzymes and peroxisome proliferation in rats treated with dehydroepiandrosterone (DHEA). Evidence of distinct zonal and sex-specific differences.

    PubMed

    Beier, K; Völkl, A; Metzger, C; Mayer, D; Bannasch, P; Fahimi, H D

    1997-08-01

    Dehydroepiandrosterone (DHEA) is an intermediate product in the synthesis of male and female sex hormones in the adrenal cortex of man. In livers of rats and mice DHEA increases the levels of cytochrome P450 IVA and peroxisomal beta-oxidation enzymes associated with peroxisome proliferation. Prolonged treatment of rats with DHEA induces liver tumors that are more frequent in females arising mainly in the periportal regions of the liver lobule (Metzger et al., Toxicol. Pathol. 23, 591-605, 1995). Because of paucity of information on hepatic zonation of peroxisomal response to DHEA and controversial reports on gender-specific differences of its effects the present study was undertaken using qualitative immunohistochemical and quantitative immunoelectron microscopical techniques in addition to Western blotting. Rats were treated for 24 weeks with 0.6% DHEA supplied with diet. Immunoblot analysis revealed marked induction of peroxisomal beta-oxidation enzymes, which by quantitative analysis was equally strong in male and female animals, whilst catalase and urate-oxidase were not increased. Cytochrome P450 IVA, in contrast, was induced significantly stronger in male than in female rats. Immunohistochemistry confirmed the induction of cytochrome P450 IVA showing a marked lobular gradient in female animals with strong induction in pericentral and almost no induction in periportal regions of the liver lobule. In male animals cytochrome P450 IVA was expressed more uniformly across the liver lobule. A similar sex specific zone-dependent response was observed for peroxisomes. DHEA induced in females a significant zonal gradient with marked peroxisome proliferation and a strong induction of peroxisomal hydratase/dehydrogenase in pericentral hepatocytes and a much smaller response in periportal regions. Livers of male animals, in contrast, showed a uniform peroxisomal proliferation to DHEA with only slight zonal differences. The striking homologies of the induction patterns of

  7. Proton-pump inhibitor-induced hypomagnesemia: Current research and proposed mechanisms

    PubMed Central

    William, Jeffrey H; Danziger, John

    2016-01-01

    Since the early reports nearly a decade ago, proton-pump inhibitor-induced hypomagnesemia (PPIH) has become a well-recognized phenomenon. While many observational studies in the inpatient and outpatient populations have confirmed the association of PPI exposure and serum magnesium concentrations, there are no prospective, controlled studies to support causation. Molecular mechanisms of magnesium transporters, including the pH-dependent regulation of transient receptor potential melastatin-6 transporters in the colonic enterocyte, have been proposed to explain the effect of PPIs on magnesium reabsorption, but may be a small part of a more complicated interplay of molecular biology, pharmacology, and genetic predisposition. This review explores the current state of research in the field of PPIH and the proposed mechanisms of this effect. PMID:26981439

  8. Visualizing inducible nitric-oxide synthase in living cells with a heme-binding fluorescent inhibitor.

    PubMed

    Panda, Koustubh; Chawla-Sarkar, Mamta; Santos, Cecile; Koeck, Thomas; Erzurum, Serpil C; Parkinson, John F; Stuehr, Dennis J

    2005-07-19

    The study of nitric-oxide synthase (NOS) physiology is constrained by the lack of suitable probes to detect NOS in living cells or animals. Here, we characterized a fluorescent inducible NOS (iNOS) inhibitor called PIF (pyrimidine imidazole FITC) and examined its utility for microscopic imaging of iNOS in living cells. PIF binding to iNOS displayed high affinity, isoform selectivity, and heme specificity, and was essentially irreversible. PIF was used to successfully image iNOS expressed in RAW264.7 cells, HEK293T cells, human A549 epithelial cells, and freshly obtained human lung epithelium. PIF was used to estimate a half-life for iNOS of 1.8 h in HEK293T cells. Our work reveals that fluorescent probes like PIF will be valuable for studying iNOS cell biology and in understanding the pathophysiology of diseases that involve dysfunctional iNOS expression.

  9. Can Exercise Ameliorate Aromatase Inhibitor-Induced Cognitive Decline in Breast Cancer Patients?

    PubMed

    Li, Cuicui; Zhou, Chenglin; Li, Rena

    2016-08-01

    Aromatase inhibitors (AIs) have been commonly used as an effective adjuvant therapy in treatment of breast cancer, especially for menopausal women with estrogen receptor-positive breast cancer. Due to the nature of aromatase, the key enzyme for endogenous estrogen synthesis, inhibitory of aromatase-induced side effects, such as cognitive impairment has been reported in both human and animal studies. While extensive evidence suggested that physical exercises can improve learning and memory activity and even prevent age-related cognitive decline, basic research revealed some common pathways between exercise and estrogen signaling that affected cognitive function. This review draws on clinical and basic studies to assess the potential impact of exercise in cognitive function from women treated with AIs for breast cancer and explore the potential mechanism and effects of exercise on estrogen-related cognition. PMID:26223800

  10. Molecular Mechanism of Silver Nanoparticles-Induced Human Osteoblast Cell Death: Protective Effect of Inducible Nitric Oxide Synthase Inhibitor

    PubMed Central

    Zielinska, Ewelina; Tukaj, Cecylia; Radomski, Marek Witold; Inkielewicz-Stepniak, Iwona

    2016-01-01

    Background Silver nanoparticles (AgNPs) show strong antibacterial properties, making them excellent candidates to be used in orthopaedic repair and regeneration. However, there are concerns regarding the cytotoxicity of AgNPs and molecular mechanisms underlying AgNPs-induced bone cells toxicity have not been elucidated. Therefore, the aim of our study was to explore mechanisms of AgNPs-induced osteoblast cell death with particular emphasis on the role of nitric oxide (NO) generated by inducible nitric oxide synthase (iNOS). Methods and Result Silver nanoparticles used in this study were 18.3±2.6 nm in size, uncoated, spherical, regular shape and their zeta potential was -29.1±2.4 mV as measured by transmission electron microscopy (TEM) and zetasizer. The release of silver (Ag) from AgNPs was measured in cell culture medium by atomic absorption spectroscopy (AAS). The exposure of human osteoblast cells (hFOB 1.19) to AgNPs at concentration of 30 or 60 μg/mL for 24 or 48 hours, respectively resulted in cellular uptake of AgNPs and changes in cell ultrastructure. These changes were associated with apoptosis and necrosis as shown by flow cytometry and lactate dehydrogenase (LDH) assay as well as increased levels of pro-apoptotic Bax and decreased levels of anti-apoptotic Bcl-2 mRNA and protein. Importantly, we have found that AgNPs elevated the levels of nitric oxide (NO) with concomitant upregulation of inducible nitric oxide synthase (iNOS) mRNA and protein. A significant positive correlation was observed between the concentration of AgNPs and iNOS at protein and mRNA level (r = 0.837, r = 0.721, respectively; p<0.001). Finally, preincubation of osteoblast cells with N-iminoethyl-l-lysine (L-NIL), a selective iNOS inhibitor, as well as treating cells with iNOS small interfering RNAs (siRNA) significantly attenuated AgNPs-induced apoptosis and necrosis. Moreover, we have found that AgNPs-induced cells death is not related to Ag dissolution is cell culture medium

  11. The novel NF-κB inhibitor IMD-0354 induces apoptosis in chronic lymphocytic leukemia.

    PubMed

    Kanduri, M; Tobin, G; Aleskog, A; Nilsson, K; Rosenquist, R

    2011-03-01

    Nuclear factor-κB (NF-κB) is an important regulator of cell survival and has been shown to be constitutively active in chronic lymphocytic leukemia (CLL) cells. Recently, a novel NF-κB inhibitor, IMD-0354 (N-(3, 5-bis-trifluoromethyl-phenyl)-5-chloro-2-hydroxy-benzamide), was shown to specifically inhibit the phosphorylation of IκBα by IkB kinases, thus preventing NF-κB release. In this study, we investigated if IMD-0354 can inhibit NF-κB activation and induce apoptosis in CLL cells in vitro. The rate of increase in apoptosis, drug sensitivity and DNA-binding activity of NF-κB were studied using Annexin V stainings, the fluorometric microculture cytotoxicity assay and electrophoretic mobility shift assay, respectively. Finally, the impact of IMD-0354 treatment on the expression of a set of apoptosis-related genes was investigated. The results clearly show that IMD-0354 induced apoptosis (mean 26%, range 8-48%) in CLL cells, independent of immunoglobulin heavy variable (IGHV) gene mutational status, and showed a dose-dependent cytotoxic effect. IMD-0354 treatment also significantly lowered the DNA-binding activity of NF-κB in CLL cells. In addition, we identified differences in expression levels of pro- and antiapoptotic genes following IMD-0354 treatment. In summary, our novel findings show that IMD-0354 can induce apoptosis in CLL cells, and thus merits further investigation as an anticancer agent in vivo. PMID:22829125

  12. The neuronal nitric oxide synthase inhibitor, 7-nitroindazole, protects against methamphetamine-induced neurotoxicity in vivo.

    PubMed

    Itzhak, Y; Ali, S F

    1996-10-01

    The present study was undertaken to investigate whether the relatively selective neuronal nitric oxide synthase (NOS) inhibitor, 7-nitroindazole (7-NI), protects against methamphetamine (METH)-induced neurotoxicity. Male Swiss Webster mice received the following treatments (i.p.; q 3 h x 3): (a) vehicle/saline, (b) 7-NI (25 mg/kg)/saline, (c) vehicle/METH (5 mg/kg), and (d) 7-NI (25 mg/kg)/METH (5 mg/kg). On the second day, groups (a) and (b) received two vehicle injections, and groups (c) and (d) received two 7-NI injections (25 mg/kg, each). Administration of vehicle/METH resulted in 68, 44, and 55% decreases in the concentration of dopamine, 3,4-dihydroxyphenylacetic acid, and homovanillic acid, respectively, and a 48% decrease in the number of [3H]mazindol binding sites in the striatum compared with control values. Treatment with 7-NI (group d) provided full protection against the depletion of dopamine and its metabolites and the loss of dopamine transporter binding sites. Administration of 7-NI/saline (group b) affected neither the tissue concentration of dopamine and its metabolites nor the binding parameters of [3H] mazindol compared with control values. 7-NI had no significant effect on animals' body temperature, and it did not affect METH-induced hyperthermia. These findings indicate a role for nitric oxide in methamphetamine-induced neurotoxicity and also suggest that blockade of NOS may be beneficial for the management of Parkinson's disease.

  13. Thrombocytopenia induced by the histone deacetylase inhibitor abexinostat involves p53-dependent and -independent mechanisms

    PubMed Central

    Ali, A; Bluteau, O; Messaoudi, K; Palazzo, A; Boukour, S; Lordier, L; Lecluse, Y; Rameau, P; Kraus-Berthier, L; Jacquet-Bescond, A; Lelièvre, H; Depil, S; Dessen, P; Solary, E; Raslova, H; Vainchenker, W; Plo, I; Debili, N

    2013-01-01

    Abexinostat is a pan histone deacetylase inhibitor (HDACi) that demonstrates efficacy in malignancy treatment. Like other HDACi, this drug induces a profound thrombocytopenia whose mechanism is only partially understood. We have analyzed its effect at doses reached in patient plasma on in vitro megakaryopoiesis derived from human CD34+ cells. When added at day 0 in culture, abexinostat inhibited CFU-MK growth, megakaryocyte (MK) proliferation and differentiation. These effects required only a short incubation period. Decreased proliferation was due to induction of apoptosis and was not related to a defect in TPO/MPL/JAK2/STAT signaling. When added later (day 8), the compound induced a dose-dependent decrease (up to 10-fold) in proplatelet (PPT) formation. Gene profiling from MK revealed a silencing in the expression of DNA repair genes with a marked RAD51 decrease at protein level. DNA double-strand breaks were increased as attested by elevated γH2AX phosphorylation level. Moreover, ATM was phosphorylated leading to p53 stabilization and increased BAX and p21 expression. The use of a p53 shRNA rescued apoptosis, and only partially the defect in PPT formation. These results suggest that HDACi induces a thrombocytopenia by a p53-dependent mechanism along MK differentiation and a p53-dependent and -independent mechanism for PPT formation. PMID:23887629

  14. MK2 inhibitor reduces alkali burn-induced inflammation in rat cornea

    PubMed Central

    Chen, Yanfeng; Yang, Wenzhao; Zhang, Xiaobo; Yang, Shu; Peng, Gao; Wu, Ting; Zhou, Yueping; Huang, Caihong; Reinach, Peter S.; Li, Wei; Liu, Zuguo

    2016-01-01

    MK2 activation by p38 MAPK selectively induces inflammation in various diseases. We determined if a MK2 inhibitor (MK2i), improves cornea wound healing by inhibiting inflammation caused by burning rat corneas with alkali. Our study, for the first time, demonstrated that MK2i inhibited alkali burn-induced MK2 activation as well as rises in inflammation based on: a) blunting rises in inflammatory index, inflammatory cell infiltration, ED1+ macrophage and PMN+ neutrophil infiltration; b) suppressing IL-6 and IL-1β gene expression along with those of macrophage inflammatory protein-1α (MIP-1α), intercellular adhesion molecule-1 (ICAM-1) and vascular cell adhesion molecule-1 (VCAM-1); c) reducing angiogenic gene expression levels and neovascularization (NV) whereas anti-angiogenic PEDF levels increased. In addition, this study found that MK2i did not affect human corneal epithelial cell (HCEC) proliferation and migration and had no detectable side effects on ocular surface integrity. Taken together, MK2i selectively inhibited alkali burn-induced corneal inflammation by blocking MK2 activation, these effects have clinical relevance in the treatment of inflammation related ocular surface diseases. PMID:27329698

  15. FK506, a calcineurin inhibitor, prevents cadmium-induced testicular toxicity in mice.

    PubMed

    Martin, Lisa Joy; Chen, Haiyan; Liao, Xiaoyan; Allayee, Hooman; Shih, Diana Mouhan; Lee, Grace Sangeun; Hovland, David Norman; Robbins, Wendie Anne; Carnes, Kay; Hess, Rex Allen; Lusis, Aldons Jake; Collins, Michael David

    2007-12-01

    Cadmium, a ubiquitous environmental contaminant, damages several major organs in humans and other mammals. The molecular mechanisms for damage are not known. At high doses (5 mg/kg cadmium chloride or higher), testicular damage in mice, rats, and other rodents includes interstitial edema, hemorrhage, and changes in the seminiferous tubules affecting spermatogenesis. Necrosis is evident by 48 h. The goal of this study was to fine map and identify the cdm gene, a gene that when mutated prevents cadmium-induced testicular toxicity in mouse strains with a mutation in this gene. A serine-threonine phosphatase, calcineurin (CN), subunit A, alpha isoform (Ppp3ca), was one of the seven candidates in the cdm region that was narrowed from 5.6 to 2.0 Mb on mouse chromosome 3. An inhibitor of CN, the immunosuppressant, FK506, prevented cadmium-induced testicular damage in five pathological categories, including vascular endothelial and seminiferous epithelial endpoints. Inductively coupled plasma-mass spectrometry revealed that FK506 protected without lowering the amount of cadmium in the testes. Ppp3ca(-/-) mice were investigated but were found to exhibit endogenous testicular abnormalities, making them an inappropriate model for determining whether the inactivation of the Ppp3ca gene would afford protection from cadmium-induced testicular toxicity. The protection afforded by FK506, found by the current study, indicated that CN is likely to be important in the mechanism of cadmium toxicity in the testis and possibly other organs. PMID:17785681

  16. Effects of a Soluble Epoxide Hydrolase Inhibitor on Lipopolysaccharide-Induced Acute Lung Injury in Mice

    PubMed Central

    Yang, Liu-Qing; Ma, Yong-Bo

    2016-01-01

    Objectives Inflammation plays a key role in the pathogenesis of acute lung injury (ALI). Soluble epoxide hydrolase (sEH) is suggested as a vital pharmacologic target for inflammation. In this study, we determined whether a sEH inhibitor, AUDA, exerts lung protection in lipopolysaccharide (LPS)-induced ALI in mice. Methods Male BALB/c mice were randomized to receive AUDA or vehicle intraperitoneal injection 4 h after LPS or phosphate buffered saline (PBS) intratracheal instillation. Samples were harvested 24 h post LPS or PBS administration. Results AUDA administration decreased the pulmonary levels of monocyte chemoattractant protein (MCP)-1 and tumor necrosis factor (TNF)-α. Improvement of oxygenation and lung edema were observed in AUDA treated group. AUDA significantly inhibited sEH activity, and elevated epoxyeicosatrienoic acids (EETs) levels in lung tissues. Moreover, LPS induced the activation of nuclear factor (NF)-κB was markedly dampened in AUDA treated group. Conclusion Administration of AUDA after the onset of LPS-induced ALI increased pulmonary levels of EETs, and ameliorated lung injury. sEH is a potential pharmacologic target for ALI. PMID:27490848

  17. TLSC702, a Novel Inhibitor of Human Glyoxalase I, Induces Apoptosis in Tumor Cells.

    PubMed

    Takasawa, Ryoko; Shimada, Nami; Uchiro, Hiromi; Takahashi, Satoshi; Yoshimori, Atsushi; Tanuma, Sei-Ichi

    2016-01-01

    Human glyoxalase I (hGLO I) is a rate-limiting enzyme in the pathway for detoxification of apoptosis-inducible methylglyoxal (MG), which is the side product of tumor-specific aerobic glycolysis. GLO I has been reported to be overexpressed in various types of cancer cells, and has been expected as an attractive target for the development of new anticancer drugs. We previously discovered a novel inhibitor of hGLO I, named TLSC702, by our in silico screening method. Here, we show that TLSC702 inhibits the proliferation of human leukemia HL-60 cells and induces apoptosis in a dose-dependent manner. In addition, TLSC702 more significantly inhibits the proliferation of human lung cancer NCI-H522 cells, which highly express GLO I, than that of GLO I lower-expressing human lung cancer NCI-H460 cells. Furthermore, this antiproliferative effect of TLSC702 on NCI-H522 cells is in a dose- and time-dependent manner. These results suggest that TLSC702 can induce apoptosis in tumor cells by GLO I inhibition, which lead to accumulation of MG. Taken together, TLSC702 could become a unique seed compound for the generation of novel chemotherapeutic drugs targeting GLO I-dependent human tumors. PMID:27150153

  18. A Receptor Tyrosine Kinase Inhibitor, Dovitinib (TKI-258), Enhances BMP-2-Induced Osteoblast Differentiation In Vitro

    PubMed Central

    Lee, Yura; Bae, Kyoung Jun; Chon, Hae Jung; Kim, Seong Hwan; Kim, Soon Ae; Kim, Jiyeon

    2016-01-01

    Dovitinib (TKI258) is a small molecule multi-kinase inhibitor currently in clinical phase I/II/III development for the treatment of various types of cancers. This drug has a safe and effective pharmacokinetic/pharmacodynamic profile. Although dovitinib can bind several kinases at nanomolar concentrations, there are no reports relating to osteoporosis or osteoblast differentiation. Herein, we investigated the effect of dovitinib on human recombinant bone morphogenetic protein (BMP)-2-induced osteoblast differentiation in a cell culture model. Dovitinib enhanced the BMP-2-induced alkaline phosphatase (ALP) induction, which is a representative marker of osteoblast differentiation. Dovitinib also stimulated the translocation of phosphorylated Smad1/5/8 into the nucleus and phosphorylation of mitogen-activated protein kinases, including ERK1/2 and p38. In addition, the mRNA expression of BMP-4, BMP-7, ALP, and OCN increased with dovitinib treatment. Our results suggest that dovitinib has a potent stimulating effect on BMP-2-induced osteoblast differentiation and this existing drug has potential for repositioning in the treatment of bone-related disorders. PMID:27025387

  19. The Role of the Endoplasmic Reticulum in Peroxisome Biogenesis

    PubMed Central

    Dimitrov, Lazar; Lam, Sheung Kwan; Schekman, Randy

    2013-01-01

    Peroxisomes are essential cellular organelles involved in lipid metabolism. Patients affected by severe peroxisome biogenesis disorders rarely survive their first year. Genetic screens in several model organisms have identified more than 30 PEX genes that are required for the formation of functional peroxisomes. Despite significant work on the PEX genes, the biogenic origin of peroxisomes remains controversial. For at least two decades, the prevailing model postulated that peroxisomes propagate by growth and fission of preexisting peroxisomes. In this review, we focus on the recent evidence supporting a new, semiautonomous model of peroxisomal biogenesis. According to this model, peroxisomal membrane proteins (PMPs) traffic from the endoplasmic reticulum (ER) to the peroxisome by a vesicular budding, targeting, and fusion process while peroxisomal matrix proteins are imported into the organelle by an autonomous, posttranslational mechanism. We highlight the contradictory conclusions reached to answer the question of how PMPs are inserted into the ER. We then review what we know and what still remains to be elucidated about the mechanism of PMP exit from the ER and the contribution of preperoxisomal vesicles to mature peroxisomes. Finally, we discuss discrepancies in our understanding of de novo peroxisome biogenesis in wild-type cells. We anticipate that resolving these key issues will lead to a more complete picture of peroxisome biogenesis. PMID:23637287

  20. Fusicoccin-induced catalase inhibitor is produced independently of H+-ATPase activation and behaves as an organic acid.

    PubMed

    Beffagna, Nicoletta; Riva, Marzia Alessandra

    2011-06-01

    The phytotoxin fusicoccin (FC) was found to induce an increase in apoplastic H₂O₂ content in Arabidopsis thaliana cells, apparently linked to the presence of an as yet unidentified catalase inhibitor detectable even in the external medium of FC-treated cells. This study, aimed to further characterize the inhibitor's features, shows that (1) FC-induced H₂O₂ accumulation increases as a function of FC concentration and correlates to the amount of inhibitor released at apoplastic level. The pattern of H+ efflux, conversely, does not fit with that of these two parameters, suggesting that neither the production nor the release of the catalase inhibitor is linked to the main role of FC in activating the plasma membrane (PM) H+-ATPase; (2) treatment with 10 µM erythrosine B (EB) early and totally inhibits net H+ and K+ fluxes across the PM, indicative of the H+ pump activity; nevertheless, also in these conditions a huge FC-induced H₂O₂ accumulation occurs, confirming that this effect is not related to the FC-induced PM H+-ATPase activation; (3) the inhibitor's release increases with time in all conditions tested and is markedly affected by extracellular pH (a higher pH value being associated to a larger efflux), in agreement with a weak acid release; and (4) the inhibitor can be almost completely recovered in a CH₂C₂-soluble fraction extracted from the incubation medium by sequential acid-base partitioning which contains nearly all of the organic acids released. These final results strongly suggest that the metabolite responsible for the FC-induced catalase inhibition belongs to the organic acid class.

  1. C1 inhibitor-mediated myocardial protection from chronic intermittent hypoxia-induced injury

    PubMed Central

    Fu, Jinrong; Guo, Furong; Chen, Cheng; Yu, Xiaoman; Hu, Ke; Li, Mingjiang

    2016-01-01

    The optimal treatment for chronic intermittent hypoxia (CIH)-induced cardiovascular injuries has yet to be determined. The aim of the current study was to explore the potential protective effect and mechanism of a C1 inhibitor in CIH in the myocardium. The present study used a rat model of CIH in which complement regulatory protein, known as C1 inhibitor (C1INH), was administered to the rats in the intervention groups. Cardiomyocyte apoptosis was detected by terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling. The expression of proteins associated with the apoptotic pathway, such as B-cell lymphoma 2 (Bcl-2), Bax and caspase-3 were detected by western blot analysis. The expression of complement C3 protein and RNA were also analyzed. C1INH was observed to improve the cardiac function in rats with CIH. Myocardial myeloperoxidase activity, a marker of neutrophil infiltration, was significantly decreased in the C1INH intervention group compared with the CIH control group, and cardiomyocyte apoptosis was significantly attenuated (P<0.05). Western blotting and reverse transcription-polymerase chain reaction analysis indicated that the protein expression levels of Bcl-2 were decreased and those of Bax were increased in the CIH group compared with the normal control group, but the protein expression levels of Bcl-2 were increased and those of Bax were decreased in the C1INH intervention group, as compared with the CIH group. Furthermore, the CIH-induced expression and synthesis of complement C3 in the myocardium were also reduced in the C1INH intervention group. C1INH, in addition to inhibiting complement activation and inflammation, preserved cardiac function in CIH-mediated myocardial cell injury through an anti-apoptotic mechanism. PMID:27698713

  2. Renoprotective effect of the xanthine oxidoreductase inhibitor topiroxostat on adenine-induced renal injury.

    PubMed

    Kamijo-Ikemori, Atsuko; Sugaya, Takeshi; Hibi, Chihiro; Nakamura, Takashi; Murase, Takayo; Oikawa, Tsuyoshi; Hoshino, Seiko; Hisamichi, Mikako; Hirata, Kazuaki; Kimura, Kenjiro; Shibagaki, Yugo

    2016-06-01

    The aim of the present study was to reveal the effect of a xanthine oxidoreductase (XOR) inhibitor, topiroxostat (Top), compared with another inhibitor, febuxostat (Feb), in an adenine-induced renal injury model. We used human liver-type fatty acid-binding protein (L-FABP) chromosomal transgenic mice, and urinary L-FABP, a biomarker of tubulointerstitial damage, was used to evaluate tubulointerstitial damage. Male transgenic mice (n = 24) were fed a 0.2% (wt/wt) adenine-containing diet. Two weeks after the start of this diet, renal dysfunction was confirmed, and the mice were divided into the following four groups: the adenine group was given only the diet containing adenine, and the Feb, high-dose Top (Top-H), and low-dose Top (Top-L) groups were given diets containing Feb (3 mg/kg), Top-H (3 mg/kg), and Top-L (1 mg/kg) in addition to adenine for another 2 wk. After withdrawal of the adenine diet, each medication was continued for 2 wk. Serum creatinine levels, the degree of macrophage infiltration, tubulointerstitial damage, renal fibrosis, urinary 15-F2t-isoprostane levels, and renal XOR activity were significantly attenuated in the kidneys of the Feb, Top-L, and Top-H groups compared with the adenine group. Serum creatinine levels in the Top-L and Top-H groups as well as renal XOR in the Top-H group were significantly lower than those in the Feb group. Urinary excretion of L-FABP in both the Top-H and Top-L groups was significantly lower than in the adenine and Feb groups. In conclusion, Top attenuated renal damage in an adenine-induced renal injury model. PMID:27029427

  3. C1 inhibitor-mediated myocardial protection from chronic intermittent hypoxia-induced injury

    PubMed Central

    Fu, Jinrong; Guo, Furong; Chen, Cheng; Yu, Xiaoman; Hu, Ke; Li, Mingjiang

    2016-01-01

    The optimal treatment for chronic intermittent hypoxia (CIH)-induced cardiovascular injuries has yet to be determined. The aim of the current study was to explore the potential protective effect and mechanism of a C1 inhibitor in CIH in the myocardium. The present study used a rat model of CIH in which complement regulatory protein, known as C1 inhibitor (C1INH), was administered to the rats in the intervention groups. Cardiomyocyte apoptosis was detected by terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling. The expression of proteins associated with the apoptotic pathway, such as B-cell lymphoma 2 (Bcl-2), Bax and caspase-3 were detected by western blot analysis. The expression of complement C3 protein and RNA were also analyzed. C1INH was observed to improve the cardiac function in rats with CIH. Myocardial myeloperoxidase activity, a marker of neutrophil infiltration, was significantly decreased in the C1INH intervention group compared with the CIH control group, and cardiomyocyte apoptosis was significantly attenuated (P<0.05). Western blotting and reverse transcription-polymerase chain reaction analysis indicated that the protein expression levels of Bcl-2 were decreased and those of Bax were increased in the CIH group compared with the normal control group, but the protein expression levels of Bcl-2 were increased and those of Bax were decreased in the C1INH intervention group, as compared with the CIH group. Furthermore, the CIH-induced expression and synthesis of complement C3 in the myocardium were also reduced in the C1INH intervention group. C1INH, in addition to inhibiting complement activation and inflammation, preserved cardiac function in CIH-mediated myocardial cell injury through an anti-apoptotic mechanism.

  4. USP7 inhibitor P22077 inhibits neuroblastoma growth via inducing p53-mediated apoptosis.

    PubMed

    Fan, Y-H; Cheng, J; Vasudevan, S A; Dou, J; Zhang, H; Patel, R H; Ma, I T; Rojas, Y; Zhao, Y; Yu, Y; Zhang, H; Shohet, J M; Nuchtern, J G; Kim, E S; Yang, J

    2013-10-17

    Neuroblastoma (NB) is a common pediatric cancer and contributes to more than 15% of all pediatric cancer-related deaths. Unlike adult tumors, recurrent somatic mutations in NB, such as tumor protein 53 (p53) mutations, occur with relative paucity. In addition, p53 downstream function is intact in NB cells with wild-type p53, suggesting that reactivation of p53 may be a viable therapeutic strategy for NB treatment. Herein, we report that the ubiquitin-specific protease 7 (USP7) inhibitor, P22077, potently induces apoptosis in NB cells with an intact USP7-HDM2-p53 axis but not in NB cells with mutant p53 or without human homolog of MDM2 (HDM2) expression. In this study, we found that P22077 stabilized p53 by inducing HDM2 protein degradation in NB cells. P22077 also significantly augmented the cytotoxic effects of doxorubicin (Dox) and etoposide (VP-16) in NB cells with an intact USP7-HDM2-p53 axis. Moreover, P22077 was found to be able to sensitize chemoresistant LA-N-6 NB cells to chemotherapy. In an in vivo orthotopic NB mouse model, P22077 significantly inhibited the xenograft growth of three NB cell lines. Database analysis of NB patients shows that high expression of USP7 significantly predicts poor outcomes. Together, our data strongly suggest that targeting USP7 is a novel concept in the treatment of NB. USP7-specific inhibitors like P22077 may serve not only as a stand-alone therapy but also as an effective adjunct to current chemotherapeutic regimens for treating NB with an intact USP7-HDM2-p53 axis.

  5. Renoprotective effect of the xanthine oxidoreductase inhibitor topiroxostat on adenine-induced renal injury.

    PubMed

    Kamijo-Ikemori, Atsuko; Sugaya, Takeshi; Hibi, Chihiro; Nakamura, Takashi; Murase, Takayo; Oikawa, Tsuyoshi; Hoshino, Seiko; Hisamichi, Mikako; Hirata, Kazuaki; Kimura, Kenjiro; Shibagaki, Yugo

    2016-06-01

    The aim of the present study was to reveal the effect of a xanthine oxidoreductase (XOR) inhibitor, topiroxostat (Top), compared with another inhibitor, febuxostat (Feb), in an adenine-induced renal injury model. We used human liver-type fatty acid-binding protein (L-FABP) chromosomal transgenic mice, and urinary L-FABP, a biomarker of tubulointerstitial damage, was used to evaluate tubulointerstitial damage. Male transgenic mice (n = 24) were fed a 0.2% (wt/wt) adenine-containing diet. Two weeks after the start of this diet, renal dysfunction was confirmed, and the mice were divided into the following four groups: the adenine group was given only the diet containing adenine, and the Feb, high-dose Top (Top-H), and low-dose Top (Top-L) groups were given diets containing Feb (3 mg/kg), Top-H (3 mg/kg), and Top-L (1 mg/kg) in addition to adenine for another 2 wk. After withdrawal of the adenine diet, each medication was continued for 2 wk. Serum creatinine levels, the degree of macrophage infiltration, tubulointerstitial damage, renal fibrosis, urinary 15-F2t-isoprostane levels, and renal XOR activity were significantly attenuated in the kidneys of the Feb, Top-L, and Top-H groups compared with the adenine group. Serum creatinine levels in the Top-L and Top-H groups as well as renal XOR in the Top-H group were significantly lower than those in the Feb group. Urinary excretion of L-FABP in both the Top-H and Top-L groups was significantly lower than in the adenine and Feb groups. In conclusion, Top attenuated renal damage in an adenine-induced renal injury model.

  6. Angiotensin-converting enzyme inhibitor (enalapril maleate) accelerates recovery of mouse skin from UVB-induced wrinkles

    SciTech Connect

    Matsuura-Hachiya, Yuko; Arai, Koji Y.; Ozeki, Rieko; Kikuta, Ayako; Nishiyama, Toshio

    2013-12-06

    Highlights: •Angiotensin converting enzyme (ACE) increases in UVB-irradiated skin. •Administration of an ACE inhibitor improved UVB-induced skin wrinkle. •ACE inhibitor improved UVB-induced epidermal hypertrophy. •ACE inhibitor improved transepidermal water loss in the UVB-irradiated skin. -- Abstract: Angiotensin-converting enzyme (ACE) activity and angiotensin II signaling regulate cell proliferation, differentiation, and tissue remodeling, as well as blood pressure, while in skin, angiotensin II signaling is involved in wound healing, inflammation, and pathological scar formation. Therefore, we hypothesized that angiotensin II is also involved in photoaging of skin. In this study, we examined the effect of enalapril maleate, an ACE inhibitor, on recovery of wrinkled skin of hairless mice exposed to long-term UVB irradiation. Immunohistochemical observation revealed that expression of ACE, angiotensin II, and angiotensin II type 1 (AT1) and type 2 (AT2) receptors in the skin was increased after UVB irradiation (3 times/week at increasing intensities for 8 weeks). Administration of enalapril maleate (5 times/week for 6 weeks, starting 1 week after 10-week irradiation) accelerated recovery from UVB-induced wrinkles, epidermal hyperplasia and epidermal barrier dysfunction, as compared with the vehicle control. Our results indicate that ACE and angiotensin II activity are involved in skin photoaging, and suggest that ACE inhibitor such as enalapril maleate may have potential for improvement of photoaged skin.

  7. Is peroxisome proliferation an obligatory precursor step in the carcinogenicity of di(2-ethylhexyl)phthalate (DEHP)?

    PubMed

    Melnick, R L

    2001-05-01

    Di(2-ethylhexyl)phthalate (DEHP), a peroxisome proliferator, has been listed by the International Agency for Research on Cancer (IARC) and by the National Toxicology Program as a possible or reasonably anticipated human carcinogen because it induces dose-related increases in liver tumors in both sexes of rats and mice. Recently, the suggestion has been advanced that DEHP should be considered unlikely to be a human carcinogen because it is claimed that the carcinogenic effects of this agent in rodents are due to peroxisome proliferation and that humans are nonresponsive to this process. An IARC working group recently downgraded DEHP to "not classifiable as to its carcinogenicity to humans" because they concluded that DEHP produces liver tumors in rats and mice by a mechanism involving peroxisome proliferation, which they considered to be not relevant to humans. The literature review presented in this commentary reveals that, although our knowledge of the mechanism of peroxisome proliferation has advanced greatly over the past 10 years, our understanding of the mechanism(s) of carcinogenicty of peroxisome proliferators remains incomplete. Most important is that published studies have not established peroxisome proliferation per se as an obligatory pathway in the carcinogenicity of DEHP. No epidemiologic studies have been reported on the potential carcinogenicity of DEHP, and cancer epidemiologic studies of hypolipidemic fibrate drugs (peroxisome proliferators) are inconclusive. Most of the pleiotropic effects of peroxisome proliferators are mediated by the peroxisome proliferator activated receptor (PPAR), a ligand-activated transcription factor that is expressed at lower levels in humans than in rats and mice. In spite of this species difference in PPAR expression, hypolipidemic fibrates have been shown to induce hypolipidemia in humans and to modulate gene expression (e.g., genes regulating lipid homeostasis) in human hepatocytes by PPAR activation. Thus, humans

  8. Inhibitors of ethylene synthesis inhibit auxin-induced stomatal opening in epidermis detached from leaves of Vicia faba L.

    PubMed

    Merritt, F; Kemper, A; Tallman, G

    2001-02-01

    Using leaf epidermis from Vicia faba, we tested whether auxin-induced stomatal opening was initiated by auxin-induced ethylene synthesis. Epidermis was dark-incubated in buffered KNO3 containing 0.1 mM alpha-napthalene acetic acid or 1 mM indole-3-acetic acid. Maximum net opening was ca. 4 micron after 6 h. Opening was reversed by 20 microM ABA, 0.1 mM CaCl2. 1-Aminocyclopropane carboxylic acid (ACC) synthase catalyzes synthesis of ACC, the immediate precursor to ethylene. Auxin-induced stomatal opening was fully inhibited by 10 microM 1-aminoethoxyvinylglycine (AVG), an ACC synthase inhibitor. In solutions containing AVG, auxin-induced opening was restored in a concentration-dependent manner by exogenous ACC, but not in control solutions lacking an auxin. ACC-mediated reversal of AVG-inhibition of stomatal opening was inhibited by alpha-aminoisobutyric acid (AIB), an inhibitor of ACC oxidase, the last enzyme in the ethylene biosynthetic pathway, by 10 microM silver thiosulfate (STS), an inhibitor of ethylene action, and by 20 microM ABA, 0.1 mM CaCl2. CoCl2, an inhibitor of ethylene synthesis, also inhibited auxin-induced opening. Both STS and CoCl2 inhibited opening induced by light or by fusicoccin, but neither light- nor fusicoccin-induced opening was inhibited by AVG. These results support the hypothesis that auxin-induced stomatal opening is mediated through auxin-induced ethylene production by guard cells.

  9. Role of Pex21p for Piggyback Import of Gpd1p and Pnc1p into Peroxisomes of Saccharomyces cerevisiae.

    PubMed

    Effelsberg, Daniel; Cruz-Zaragoza, Luis Daniel; Tonillo, Jason; Schliebs, Wolfgang; Erdmann, Ralf

    2015-10-16

    Proteins designated for peroxisomal protein import harbor one of two common peroxisomal targeting signals (PTS). In the yeast Saccharomyces cerevisiae, the oleate-induced PTS2-dependent import of the thiolase Fox3p into peroxisomes is conducted by the soluble import receptor Pex7p in cooperation with the auxiliary Pex18p, one of two supposedly redundant PTS2 co-receptors. Here, we report on a novel function for the co-receptor Pex21p, which cannot be fulfilled by Pex18p. The data establish Pex21p as a general co-receptor in PTS2-dependent protein import, whereas Pex18p is especially important for oleate-induced import of PTS2 proteins. The glycerol-producing PTS2 protein glycerol-3-phosphate dehydrogenase Gpd1p shows a tripartite localization in peroxisomes, in the cytosol, and in the nucleus under osmotic stress conditions. We show the following: (i) Pex21p is required for peroxisomal import of Gpd1p as well as a key enzyme of the NAD(+) salvage pathway, Pnc1p; (ii) Pnc1p, a nicotinamidase without functional PTS2, is co-imported into peroxisomes by piggyback transport via Gpd1p. Moreover, the specific transport of these two enzymes into peroxisomes suggests a novel regulatory role for peroxisomes under various stress conditions.

  10. In vitro effects of cysteine protease inhibitors on Trichomonas foetus-induced cytopathic changes in porcine intestinal epithelial cells.

    PubMed

    Tolbert, M Katherine; Brand, Mabre D; Gould, Emily N

    2016-08-01

    OBJECTIVE To investigate the effects of specific cysteine protease (CP) inhibitors on cytopathic changes to porcine intestinal epithelial cells induced by Tritrichomonas foetus isolated from naturally infected cats. SAMPLE T foetus isolates from 4 naturally infected cats and nontransformed porcine intestinal epithelial cells. PROCEDURES T foetus isolates were treated with or without 0.1 to 1.0mM of the CP inhibitors antipain, cystatin, leupeptin, and chymostatin and the vinyl sulfone inhibitors WRR-483 and K11777. In-gel gelatin zymography was performed to evaluate the effects of these inhibitors on CP activity of T foetus isolates. Each treated or untreated isolate was also cocultured with monolayers of porcine intestinal epithelial cells for 24 hours, and cytopathic effects of T foetus were evaluated by light microscopy and crystal violet spectrophotometry. RESULTS Results of in-gel gelatin zymography suggested an ability of WRR-483, K11777, and cystatin to target specific zones of CP activity of the T foetus isolates. These inhibitors had no effect on T foetus growth, and the cytopathic changes to the intestinal epithelium induced by all 4 T foetus isolates were significantly inhibited. CONCLUSIONS AND CLINICAL RELEVANCE This study revealed that certain protease inhibitors were capable of inhibiting regions of CP activity (which has been suggested to cause intestinal cell damage in cats) in T foetus organisms and of ameliorating T foetus-induced cytopathic changes to porcine intestinal epithelium in vitro. Although additional research is needed, these inhibitors might be useful in the treatment of cats with trichomonosis. PMID:27463553

  11. The novel HDAC inhibitor AR-42-induced anti-colon cancer cell activity is associated with ceramide production

    SciTech Connect

    Xu, Weihong; Xu, Bin; Yao, Yiting; Yu, Xiaoling; Shen, Jie

    2015-08-07

    In the current study, we investigated the potential activity of AR-42, a novel histone deacetylase (HDAC) inhibitor, against colon cancer cells. Our in vitro results showed that AR-42 induced ceramide production, exerted potent anti-proliferative and pro-apoptotic activities in established (SW-620 and HCT-116 lines) and primary human colon cancer cells. Exogenously-added sphingosine 1-phosphate (S1P) suppressed AR-42-induced activity, yet a cell-permeable ceramide (C4) facilitated AR-42-induced cytotoxicity against colon cancer cells. In addition, AR-42-induced ceramide production and anti-colon cancer cell activity were inhibited by the ceramide synthase inhibitor fumonisin B1, but were exacerbated by PDMP, which is a ceramide glucosylation inhibitor. In vivo, oral administration of a single dose of AR-42 dramatically inhibited SW-620 xenograft growth in severe combined immunodeficient (SCID) mice, without inducing overt toxicities. Together, these results show that AR-42 dramatically inhibits colon cancer cell proliferation in vitro and in vivo, and ceramide production might be the key mechanism responsible for its actions. - Highlights: • AR-42 is anti-proliferative against primary/established colon cancer cells. • AR-42 induces significant apoptotic death in primary/established colon cancer cells. • Ceramide production mediates AR-42-induced cytotoxicity in colon cancer cells. • AR-42 oral administration potently inhibits SW-620 xenograft growth in SCID mice.

  12. Pex19p contributes to peroxisome inheritance in the association of peroxisomes to Myo2p.

    PubMed

    Otzen, Marleen; Rucktäschel, Robert; Thoms, Sven; Emmrich, Kerstin; Krikken, Arjen M; Erdmann, Ralf; van der Klei, Ida J

    2012-07-01

    During budding of yeast cells peroxisomes are distributed over mother cell and bud, a process that involves the myosin motor protein Myo2p and the peroxisomal membrane protein Inp2p. Here, we show that Pex19p, a peroxin implicated in targeting and complex formation of peroxisomal membrane proteins, also plays a role in peroxisome partitioning. Binding studies revealed that Pex19p interacts with the cargo-binding domain of Myo2p. We identified mutations in Myo2p that specifically reduced binding to Pex19p, but not to Inp2p. The interaction between Myo2p and Pex19p was also reduced by a mutation that blocked Pex19p farnesylation. Microscopy revealed that the Pex19p-Myo2p interaction is important for peroxisome inheritance, because mutations that affect this interaction hamper peroxisome inheritance in vivo. Together these data suggest that both Inp2p and Pex19p are required for proper association of peroxisomes to Myo2p.

  13. De novo peroxisome biogenesis: Evolving concepts and conundrums.

    PubMed

    Agrawal, Gaurav; Subramani, Suresh

    2016-05-01

    Peroxisomes proliferate by growth and division of pre-existing peroxisomes or could arise de novo. Though the de novo pathway of peroxisome biogenesis is a more recent discovery, several studies have highlighted key mechanistic details of the pathway. The endoplasmic reticulum (ER) is the primary source of lipids and proteins for the newly-formed peroxisomes. More recently, an intricate sorting process functioning at the ER has been proposed, that segregates specific PMPs first to peroxisome-specific ER domains (pER) and then assembles PMPs selectively into distinct pre-peroxisomal vesicles (ppVs) that later fuse to form import-competent peroxisomes. In addition, plausible roles of the three key peroxins Pex3, Pex16 and Pex19, which are also central to the growth and division pathway, have been suggested in the de novo process. In this review, we discuss key developments and highlight the unexplored avenues in de novo peroxisome biogenesis.

  14. Peroxin Puzzles and Folded Freight: Peroxisomal Protein Import in Review

    NASA Astrophysics Data System (ADS)

    Crookes, Wendy J.; Olsen, Laura J.

    Peroxisomes are organelles that perform a variety of functions, including the metabolism of hydrogen peroxide and the oxidation of fatty acids. Peroxisomes do not possess organellar DNA; all peroxisomal matrix proteins are posttranslationally translocated into the organelle. The mechanism of peroxisomal protein translocation has been the subject of vigorous research in the past decade. Many of the proteins (peroxins, abbreviated Pex) that play critical roles in peroxisome biogenesis have been identified through functional complementation of yeast strains and of Chinese hamster ovary cell lines that are defective in peroxisome biogenesis. Researchers are now turning towards biochemical and genetic analyses of these peroxins to define their roles in peroxisome biogenesis and to discover interacting protein partners. Evidence suggests that some of the interacting partners include molecular chaperones. Several current models for peroxisomal protein import are presented.

  15. Peroxisomes, cell senescence, and rates of aging☆

    PubMed Central

    Giordano, Courtney R.; Terlecky, Stanley R.

    2013-01-01

    The peroxisome is functionally integrated into an exquisitely complex network of communicating endomembranes which is only beginning to be appreciated. Despite great advances in identifying essential components and characterizing molecular mechanisms associated with the organelle’s biogenesis and function, there is a large gap in our understanding of how peroxisomes are incorporated into metabolic pathways and subcellular communication networks, how they contribute to cellular aging, and where their influence is manifested on the initiation and progression of degenerative disease. In this review, we summarize recent evidence pointing to the organelle as an important regulator of cellular redox balance with potentially far-reaching effects on cell aging and the genesis of human disease. The roles of the organelle in lipid homeostasis, anaplerotic reactions, and other critical metabolic and biochemical processes are addressed elsewhere in this volume. This article is part of a Special Issue entitled: Metabolic Functions and Biogenesis of Peroxisomes in Health and Disease. PMID:22497955

  16. Peroxisomes, cell senescence, and rates of aging.

    PubMed

    Giordano, Courtney R; Terlecky, Stanley R

    2012-09-01

    The peroxisome is functionally integrated into an exquisitely complex network of communicating endomembranes which is only beginning to be appreciated. Despite great advances in identifying essential components and characterizing molecular mechanisms associated with the organelle's biogenesis and function, there is a large gap in our understanding of how peroxisomes are incorporated into metabolic pathways and subcellular communication networks, how they contribute to cellular aging, and where their influence is manifested on the initiation and progression of degenerative disease. In this review, we summarize recent evidence pointing to the organelle as an important regulator of cellular redox balance with potentially far-reaching effects on cell aging and the genesis of human disease. The roles of the organelle in lipid homeostasis, anaplerotic reactions, and other critical metabolic and biochemical processes are addressed elsewhere in this volume. This article is part of a Special Issue entitled: Metabolic Functions and Biogenesis of Peroxisomes in Health and Disease.

  17. PPARÁ-DEPENDENT GENE EXPRESSION CHANGES IN THE MOUSE LIVER AFTER EXPOSURE TO PEROXISOME PROLIFERATORS

    EPA Science Inventory

    Peroxisome proliferators (PP) are a large class of structurally diverse chemicals that mediate their effects in the liver mainly through the PP-activated receptor ¿ (PPARα). Development of PP induced hepatocarcinogenesis in mouse liver is known to be dependent on PPAR&#...

  18. IDENTIFICATION OF EARLY MOLECULAR EVENTS AFTER PEROXISOME PROLIFERATOR EXPOSURE IN THE RODENT LIVER

    EPA Science Inventory

    Peroxisome proliferators (PP) are a large class of structurally diverse chemicals that mediate their effects in the liver mainly through the PP-activated receptor α(PPARα). Development of PP induced hepatocarcinogenesis in mouse liver is known to be dependent on PPARα but do...

  19. Activity of Pichia pastoris alternative cis-prenyltransferase is correlated with proliferation of peroxisomes.

    PubMed

    Skoneczny, Marek; Kludkiewicz, Barbara; Swiezewska, Ewa; Szkopinska, Anna

    2006-02-01

    We have investigated dolichol synthesis in yeast Pichia pastoris. Growth of these cells on methanol causes peroxisome proliferation and induction of peroxisomal enzymes. Twenty-four hours methanol treatment was sufficient for the appearance of longer-chain dolichols. Less specific oleic acid induction needed 48 h for the synthesis of longer dolichol family with typical one still present. Cells cultured in non-inducing conditions for 48 h did not reveal the presence of additional dolichol family. Peroxisomes purified from oleic acid treated cells synthesize in vitro polyprenols longer by two isoprene residues than those synthesized by microsomal fraction from glucose culture. These observations lead us to suggest that chain length of dolichols synthesized in yeast cell may depend on the carbon and energy source supply which mobilizes metabolic pathways localized to different cellular compartments.

  20. Inhibition of peroxisomal fatty acyl-CoA oxidase by antimycin A.

    PubMed Central

    Vamecq, J; Schepers, L; Parmentier, G; Mannaerts, G P

    1987-01-01

    Peroxisomal fatty acyl-CoA oxidase was inhibited by micromolar concentrations of antimycin A, an inhibitor of mitochondrial respiration. The inhibition was observed with all three substrates tested, i.e. palmitoyl-CoA, trihydroxycoprostanoyl-CoA and hexadecanedioyl-CoA. The peroxisomal D-amino acid oxidase was also inhibited by antimycin, but the peroxisomal L-alpha-hydroxyacid oxidase and uric acid oxidase and the mitochondrial monoamine oxidase were not. The degree of inhibition of acyl-CoA oxidase by antimycin was strongly dependent on the amount of cellular protein present in the assay mixture: at a fixed antimycin concentration, the inhibition was gradually lost with increasing protein concentrations. At a fixed cellular protein concentration in the assay mixtures, the mitochondrial oxidation of glutamate or palmitoylcarnitine was inhibited at antimycin concentrations that were much lower than those required for the inhibition of fatty acyl-CoA oxidase. Our results, nevertheless, demonstrate that antimycin A must be used with caution, when it is added to homogenates or subcellular fractions in order to distinguish between mitochondrial and peroxisomal fatty acid oxidation. PMID:3435468

  1. Charcot-Marie-Tooth disease-associated mutants of GDAP1 dissociate its roles in peroxisomal and mitochondrial fission

    PubMed Central

    Huber, Nina; Guimaraes, Sofia; Schrader, Michael; Suter, Ueli; Niemann, Axel

    2013-01-01

    Mitochondria and peroxisomes can be fragmented by the process of fission. The fission machineries of both organelles share a set of proteins. GDAP1 is a tail-anchored protein of mitochondria and induces mitochondrial fragmentation. Mutations in GDAP1 lead to Charcot-Marie-Tooth disease (CMT), an inherited peripheral neuropathy, and affect mitochondrial dynamics. Here, we show that GDAP1 is also targeted to peroxisomes mediated by the import receptor Pex19. Knockdown of GDAP1 leads to peroxisomal elongation that can be rescued by re-expressing GDAP1 and by missense mutated forms found in CMT patients. GDAP1-induced peroxisomal fission is dependent on the integrity of its hydrophobic domain 1, and on Drp1 and Mff, as is mitochondrial fission. Thus, GDAP1 regulates mitochondrial and peroxisomal fission by a similar mechanism. However, our results reveal also a more critical role of the amino-terminal GDAP1 domains, carrying most CMT-causing mutations, in the regulation of mitochondrial compared to peroxisomal fission. PMID:23628762

  2. The NADPH oxidase inhibitor apocynin induces nitric oxide synthesis via oxidative stress

    SciTech Connect

    Riganti, Chiara

    2008-05-01

    We have recently shown that apocynin elicits an oxidative stress in N11 mouse glial cells and other cell types. Here we report that apocynin increased the accumulation of nitrite, the stable derivative of nitric oxide (NO), in the extracellular medium of N11 cell cultures, and the NO synthase (NOS) activity in cell lysates. The increased synthesis of NO was associated with increased expression of inducible NOS (iNOS) mRNA, increased nuclear translocation of the redox-sensitive transcription factor NF-{kappa}B and decreased intracellular level of its inhibitor IkB{alpha}. These effects, accompanied by increased production of H{sub 2}O{sub 2}, were very similar to those observed after incubation with bacterial lipopolysaccharide (LPS) and were inhibited by catalase. These results suggest that apocynin, similarly to LPS, induces increased NO synthesis by eliciting a generation of reactive oxygen species (ROS), which in turn causes NF-{kappa}B activation and increased expression of iNOS. Therefore, the increased bioavailability of NO reported in the literature after in vivo or in vitro treatments with apocynin might depend, at least partly, on the drug-elicited induction of iNOS, and not only on the inhibition of NADPH oxidase and the subsequent decreased scavenging of NO by oxidase-derived ROS, as it is often supposed.

  3. A lysophosphatidic acid analogue is revealed as a potent inhibitor of phosphatidylcholine synthesis, inducing apoptosis.

    PubMed Central

    Gueguen, Geneviéve; Granci, Virginie; Rogalle, Pierre; Briand-Mésange, Fabienne; Wilson, Michéle; Klaébé, Alain; Tercé, François; Chap, Hugues; Salles, Jean-Pierre; Simon, Marie-Françoise; Gaits, Frédérique

    2002-01-01

    A previous study demonstrated that cross-desensitization experiments performed with the lysophosphatidic acid (LPA) analogues (R)- and (S)-N-palmitoyl-norleucinol 1-phosphate (PNPAs) inhibited LPA-induced platelet aggregation without any stereospecificity. Here we report opposite biological effects of the two enantiomers on mitogenesis of IMR-90 fibroblasts in relation to their respective metabolism. (R)PNPA was proliferative, while (S)PNPA induced apoptosis by specifically inhibiting phosphatidylcholine biosynthesis at the last step of the CDP-choline pathway controlled by cholinephosphotransferase. This effect was not direct but required dephosphorylation of PNPAs by ecto-lipid phosphate phosphatase before cellular uptake of the generated N-palmitoyl-norleucinols (PNOHs). Inhibition of cholinephosphotransferase by the derivative (S)PNOH was confirmed by an in vitro assay. (S)PNPA proapoptotic effects led us to clarify the mechanism linking cholinephosphotransferase inhibition to apoptosis. Three proapoptotic responses were observed: the activation of caspase-3, the production of ceramides from newly synthesized pools (as demonstrated by the inhibitor Fumonisin B1) and finally the activation of stress-activated protein kinase, p38 and c-Jun N-terminal kinases 1/2, as a result of ceramide increase. Thus our data demonstrate that synthetic analogues of LPA might display stereospecific effects leading to apoptosis independently of classical LPA-activated pathways. PMID:12197836

  4. CT-2576, an inhibitor of phospholipid signaling, suppresses constitutive and induced expression of human immunodeficiency virus.

    PubMed Central

    Leung, D W; Peterson, P K; Weeks, R; Gekker, G; Chao, C C; Kaplan, A H; Balantac, N; Tompkins, C; Underiner, G E; Bursten, S

    1995-01-01

    Viruses such as human immunodeficiency virus (HIV) require cellular activation for expression. Cellular activation in lymphoid cells is associated with augmented accumulation of certain phosphatidic acid (PA) species derived from the hydrolysis of glycan phosphatidylinositol (GPI). This suggests that activation of a phospholipid pathway may play a role in initiation of viral replication. To test this hypothesis, we examined the effect of tat gene expression on the production of cellular PA species, as the Tat protein is essential for HIV expression and has been implicated in activating the expression of multiple host cellular genes. Expression of tat increased the expression of PA. We then tested whether synthetic inhibitors of PA metabolism would inhibit activation of the HIV long terminal repeat by Tat and tumor necrosis factor alpha (TNF-alpha). CT-2576 suppressed both PA generation induced by Tat and HIV long terminal repeat-directed gene expression in response to Tat or TNF-alpha at a posttranscriptional step. CT-2576 also inhibited constitutive as well as TNF-alpha- and interleukin 6-induced expression of HIV p24 antigen in chronically infected U1 cells and in peripheral blood lymphocytes acutely infected with a clinical isolate of HIV. Pharmacological inhibition of synthesis of selected PA species may therefore provide a therapeutic approach to suppression of HIV replication. Images Fig. 1 Fig. 3 Fig. 5 PMID:7761405

  5. A Sphingolipid Inhibitor Induces a Cytokinesis Arrest and Blocks Stage Differentiation in Giardia lamblia▿

    PubMed Central

    Sonda, Sabrina; Štefanić, Saša; Hehl, Adrian B.

    2008-01-01

    Sphingolipid biosynthesis pathways have recently emerged as a promising target for therapeutic intervention against pathogens, including parasites. A key step in the synthesis of complex sphingolipids is the glucosylation of ceramide, mediated by glucosylceramide (GlcCer) synthase, whose activity can be inhibited by PPMP (1-phenyl-2-palmitoylamino-3-morpholino-1-propanol). In this study, we investigated whether PPMP inhibits the proliferation and differentiation of the pathogenic parasite Giardia lamblia, the major cause of parasite-induced diarrhea worldwide. PPMP was found to block in vitro parasite replication in a dose-dependent manner, with a 50% inhibitory concentration of 3.5 μM. The inhibition of parasite replication was irreversible at 10 μM PPMP, a concentration that did not affect mammalian cell metabolism. Importantly, PPMP inhibited the completion of cell division at a specific stage in late cytokinesis. Microscopic analysis of cells incubated with PPMP revealed the aberrant accumulation of cellular membranes belonging to the endoplasmic reticulum network in the caudal area of the parasites. Finally, PPMP induced a 90% reduction in G. lamblia differentiation into cysts, the parasite stage responsible for the transmission of the disease. These results show that PPMP is a powerful inhibitor of G. lamblia in vitro and that as-yet-uncharacterized sphingolipid biosynthetic pathways are potential targets for the development of anti-G. lamblia agents. PMID:18086854

  6. A sphingolipid inhibitor induces a cytokinesis arrest and blocks stage differentiation in Giardia lamblia.

    PubMed

    Sonda, Sabrina; Stefanic, Sasa; Hehl, Adrian B

    2008-02-01

    Sphingolipid biosynthesis pathways have recently emerged as a promising target for therapeutic intervention against pathogens, including parasites. A key step in the synthesis of complex sphingolipids is the glucosylation of ceramide, mediated by glucosylceramide (GlcCer) synthase, whose activity can be inhibited by PPMP (1-phenyl-2-palmitoylamino-3-morpholino-1-propanol). In this study, we investigated whether PPMP inhibits the proliferation and differentiation of the pathogenic parasite Giardia lamblia, the major cause of parasite-induced diarrhea worldwide. PPMP was found to block in vitro parasite replication in a dose-dependent manner, with a 50% inhibitory concentration of 3.5 muM. The inhibition of parasite replication was irreversible at 10 muM PPMP, a concentration that did not affect mammalian cell metabolism. Importantly, PPMP inhibited the completion of cell division at a specific stage in late cytokinesis. Microscopic analysis of cells incubated with PPMP revealed the aberrant accumulation of cellular membranes belonging to the endoplasmic reticulum network in the caudal area of the parasites. Finally, PPMP induced a 90% reduction in G. lamblia differentiation into cysts, the parasite stage responsible for the transmission of the disease. These results show that PPMP is a powerful inhibitor of G. lamblia in vitro and that as-yet-uncharacterized sphingolipid biosynthetic pathways are potential targets for the development of anti-G. lamblia agents. PMID:18086854

  7. JTP-103237, a novel monoacylglycerol acyltransferase inhibitor, modulates fat absorption and prevents diet-induced obesity.

    PubMed

    Okuma, Chihiro; Ohta, Takeshi; Tadaki, Hironobu; Hamada, Hiromi; Oda, Tomohiro; Taniuchi, Hideyuki; Yamanaka, Kenji; Ishii, Yukihito; Ohe, Yasuhiro; Yata, Shinji; Nishiu, Jun; Aratsu, Yusuke; Oshida, Shinichi; Kume, Shinichi; Kakutani, Makoto

    2015-07-01

    Monoacylglycerol acyltransferase 2 (MGAT2) plays an important role in intestinal fat absorption. We discovered the novel MGAT2 inhibitor, JTP-103237, and evaluated its pharmacological profile. JTP-103237 selectively inhibited MGAT2 without remarkable species differences and reduced absorbed lipids in circulation. After lipid administration, JTP-103237 slightly but significantly decreased triglyceride content in proximal small intestine and significantly increased the lipids content in the distal small intestine. In addition, JTP-103237 significantly increased MGAT substrate (monoacylglycerol and fatty acid) content in the small intestine. JTP-103237 increased plasma peptide YY levels after lipid loading and reduced food intake in a dietary fat-dependent manner. After chronic treatment, JTP-103237 significantly decreased body weight and increased O2 consumption in the early dark phase in high fat diet induced obese (DIO) mice. Moreover, JTP-103237 improved glucose tolerance and decreased fat weight and hepatic triglyceride content in DIO mice. Our findings indicate that JTP-103237 prevents diet-induced obesity by inhibiting intestinal MGAT2 and has unique properties as a drug for the treatment of obesity.

  8. Small molecule inhibitors of Clostridium difficile toxin B-induced cellular damage.

    PubMed

    Tam, John; Beilhartz, Greg L; Auger, Anick; Gupta, Pulkit; Therien, Alex G; Melnyk, Roman A

    2015-02-19

    Clostridium difficile causes life-threatening diarrhea through the actions of its homologous toxins TcdA and TcdB on human colonocytes. Therapeutic agents that block toxin-induced damage are urgently needed to prevent the harmful consequences of toxin action that are not addressed with current antibiotic-based treatments. Here, we developed an imaging-based phenotypic screen to identify small molecules that protected human cells from TcdB-induced cell rounding. A series of structurally diverse compounds with antitoxin activity were identified and found to act through one of a small subset of mechanisms, including direct binding and sequestration of TcdB, inhibition of endosomal maturation, and noncompetitive inhibition of the toxin glucosyltransferase activity. Distinct classes of inhibitors were used further to dissect the determinants of the toxin-mediated necrosis phenotype occurring at higher doses of toxin. These findings validate and inform novel targeting strategies for discovering small molecule agents to treat C. difficile infection. PMID:25619932

  9. Beneficial effects of nilotinib, tyrosine kinase inhibitor on cyclosporine-A induced renal damage in rats.

    PubMed

    Nader, Manar A; Attia, Ghalia M

    2016-04-01

    Nilotinib is a known tyrosine kinase inhibitor that has been approved for treatment of leukemia. The possible protective effect of nilotinib on cyclosporine A-induced nephropathy was investigated in this study and the possible underlying mechanism was explored. Nilotinib (25mg/kg, orally) and cyclosporine A (15 mg/kg/day, subcutaneous) were given to male SD rats for 28 days. Cyclosporine A alone was found to significantly increase serum creatinine, blood urea nitrogen, lactate dehydrogenase, urinary micrototal protein, renal thiobarbituric acid reactive substance, Bax, cytosol cytochrome c release and nuclear factor kappa B activation. Moreover, cyclosporine A significantly reduced serum albumin, creatinine clearance, urinary total antioxidant, superoxide dismutase, glutathione and Bcl2 protein levels. Pathological results showed that in the model group; there was an obvious shrinkage and congestion of the glomeruli and widening of urinary spaces of renal corpuscles, in addition to marked renal tubular injury and fibrosis, while in the group pretreated with nilotinib all measured serum, renal and pathological changes were significantly reduced. This protective effect of nilotinib is linked to the enhanced antioxidant status and reduced inflammation and apoptosis induced by cyclosporine A.

  10. Inhibitors of differentiation-1 promotes nitrosopyrrolidine-induced transformation of HPV 16-immortalized cervical epithelial cell

    PubMed Central

    Xie, Lingxia; Li, Jinke; Zhang, Yi; Liu, Bao; Peng, Xue; Lin, Yong; Xu, Wenming; Hu, Lina

    2014-01-01

    Our previous study implied a correlation between inhibitors of differentiation-1 (Id-1) and cervical cancer development. However, how Id-1 contributes to cervical carcinogenesis is unknown. In the present study, we used an in vitro transformation model to investigate the role of Id-1 in the transformation of cervical cells. Human papillomavirus (HPV)-immortalized cervical epithelial cells (H8) were successfully transformed by exposure to the carcinogen N-nitrosopyrrolidine (NPYR). The expression of both Id-1 RNA and protein was significantly increased in transformed H8 cells, suggesting a possible role of Id-1 in cervical cell transformation. Ectopic expression of Id-1 in H8 cells potentiated NPYR-induced cell transformation. In contrast, silencing of Id-1 suppressed NPYR-induced H8 cell transformation. In addition, the expression of HPV E6 and E7 oncoproteins was upregulated while that of the tumor suppressors p53 and pRb was suppressed after H8 cell transformation. Our results suggest that Id-1 plays an oncogenic role in HPV-related cervical carcinogenesis, which sheds light on cervical cancer development mechanisms and implies that Id-1 is a potential target for cervical cancer prevention and therapy. PMID:24628854

  11. MET inhibitor PHA-665752 suppresses the hepatocyte growth factor-induced cell proliferation and radioresistance in nasopharyngeal carcinoma cells

    SciTech Connect

    Liu, Tongxin; Li, Qi; Sun, Quanquan; Zhang, Yuqin; Yang, Hua; Wang, Rong; Chen, Longhua; Wang, Wei

    2014-06-20

    Highlights: • We demonstrated that irradiation induced MET overexpression and activation. • The aberrant MET signal mediated by HGF induced proliferation and radioresistance of NPC cells. • MET inhibitor PHA-665752 effectively suppressed HGF induced cell proliferation and radioresistance in NPC cells. • PHA-665752 suppressed the three downstream pathway of HGF/MET signal in a dose-dependent manner. - Abstract: Although ionizing radiation (IR) has provided considerable improvements in nasopharyngeal carcinoma (NPC), in subsets of patients, radioresistance is still a major problem in the treatment. In this study, we demonstrated that irradiation induced MET overexpression and activation, and the aberrant MET signal mediated by hepatocyte growth factor (HGF) induced radioresistance. We also found that MET inhibitor PHA-665752 effectively suppressed HGF induced cell proliferation and radioresistance in NPC cells. Further investigation indicated that PHA-665752 suppressed the phosphorylation of the Akt, ERK1/2, and STAT3 proteins in a dose-dependent manner. Our data indicated that the combination of IR with a MET inhibitor, such as PHA-665752, might be a promising therapeutic strategy for NPC.

  12. Expression of the Salmonella spp. virulence factor SifA in yeast alters Rho1 activity on peroxisomes.

    PubMed

    Vinh, Dani B N; Ko, Dennis C; Rachubinski, Richard A; Aitchison, John D; Miller, Samuel I

    2010-10-15

    The Salmonella typhimurium effector protein SifA regulates the assembly and tubulation of the Salmonella phagosome. SifA localizes to the phagosome and interacts with the membrane via its prenylated tail. SifA is a structural homologue of another bacterial effector that acts as a GTP-exchange factor for Rho family GTPases and can bind GDP-RhoA. When coexpressed with a bacterial lipase that is activated by RhoA, SifA can induce tubulation of mammalian endosomes. In an effort to develop a genetic system to study SifA function, we expressed SifA and characterized its activity in yeast. GFP-SifA predominantly localized to yeast peroxisomal membranes. Under peroxisome-inducing conditions, GFP-SifA reduced the number of free peroxisomes and promoted the formation of large peroxisomes with membrane invaginations. GFP-SifA activity depended on the recruitment to peroxisomes of wild-type Rho1p and Pex25p, a receptor for Rho1p. GFP-SifA could also rescue the actin organization defects in pex25Δ and rho1 mutants, suggesting that SifA may recruit and potentiate Rho1p activity. We reexamined the distribution of GFP-SifA in mammalian cells and found the majority colocalizing with LAMP1-positive compartment and not with the peroxisomal marker PMP70. Together, these data suggest that SifA may use a similar mode of action via Rho proteins to alter yeast peroxisomal and mammalian endosomal membranes. Further definition of SifA activity on yeast peroxisomes could provide more insight into its role in regulating host membrane dynamics and small GTPases.

  13. HDAC inhibitors induce global changes in histone lysine and arginine methylation and alter expression of lysine demethylases.

    PubMed

    Lillico, Ryan; Sobral, Marina Gomez; Stesco, Nicholas; Lakowski, Ted M

    2016-02-01

    Histone deacetylase (HDAC) inhibitors are cancer treatments that inhibit the removal of the epigenetic modification acetyllysine on histones, resulting in altered gene expression. Such changes in expression may influence other histone epigenetic modifications. We describe a validated liquid chromatography-tandem mass spectrometry (LC-MS/MS) method to quantify lysine acetylation and methylation and arginine methylation on histones extracted from cultured cells treated with HDAC inhibitors. The HDAC inhibitors vorinostat, mocetinostat and entinostat induced 400-600% hyperacetylation in HEK 293 and K562 cells. All HDAC inhibitors decreased histone methylarginines in HEK 293 cells but entinostat produced dose dependent reductions in asymmetric dimethylarginine, not observed in K562 cells. Vorinostat produced increases in histone lysine methylation and decreased expression of some lysine demethylases (KDM), measured by quantitative PCR. Entinostat had variable effects on lysine methylation and decreased expression of some KDM while increasing expression of others. Mocetinostat produced dose dependent increases in histone lysine methylation by LC-MS/MS. This was corroborated with a multiplex colorimetric assay showing increases in histone H3 lysine 4, 9, 27, 36 and 79 methylation. Increases in lysine methylation were correlated with dose dependent decreases in the expression of seven KDM. Mocetinostat functions as an HDAC inhibitor and a de facto KDM inhibitor.

  14. Etodolac, a cyclooxygenase-2 inhibitor, attenuates paclitaxel-induced peripheral neuropathy in a mouse model of mechanical allodynia.

    PubMed

    Ito, Sunao; Tajima, Koyuki; Nogawa, Masaki; Inoue, Naoki; Kyoi, Takashi; Takahashi, Yosuke; Sasagawa, Takahiro; Nakamura, Akio; Kotera, Takashi; Ueda, Makoto; Yamashita, Yasuhiro; Banno, Kouji

    2012-07-01

    The effect of the cyclooxygenase-2 (COX-2) inhibitor etodolac on the mechanical allodynia induced by paclitaxel was investigated in mice and compared with the effects of the nonselective COX inhibitors indomethacin and diclofenac, the selective COX-2 inhibitor celecoxib, the calcium channel α(2)δ subunit inhibitor pregabalin, the sodium channel blocker mexiletine, and the serotonin-norepinephrine reuptake inhibitor duloxetine. The decrease in the paw-withdrawal threshold induced by paclitaxel was reversed by oral administration of etodolac at 10 mg/kg but was not affected by indomethacin, diclofenac, or celecoxib. The antiallodynic effect of etodolac gradually increased during repeated administration, and after 2 weeks the paw-withdrawal threshold at the preadministration point was significantly increased. Pregabalin, duloxetine, and mexiletine also showed an antiallodynic effect in this model. Whereas pregabalin had a preadministration effect similar to that of etodolac during repeated administration, mexiletine or duloxetine had no such effect. There was almost no difference in the distribution of etodolac and diclofenac in nervous tissue, indicating that COX inhibition is unlikely to be involved in the antiallodynic effect of etodolac. Etodolac did not show a neuroprotective effect against morphological transformations such as the axonal degeneration induced by paclitaxel. Instead, etodolac probably acts at the level of functional changes accompanying paclitaxel treatment, such as alterations in the activation state of components of the pain transmission pathway. Our findings suggest that etodolac attenuates paclitaxel-induced peripheral neuropathy by a COX-independent pathway and that it might be useful for the treatment of paclitaxel-induced peripheral neuropathy. PMID:22460833

  15. ABCD1 deletion-induced mitochondrial dysfunction is corrected by SAHA: implication for adrenoleukodystrophy

    PubMed Central

    Baarine, Mauhamad; Beeson, Craig; Singh, Avtar; Singh, Inderjit

    2015-01-01

    X-linked Adrenoleukodystrophy (X-ALD), an inherited peroxisomal metabolic neurodegenerative disorder, is caused by mutations/deletions in the ABCD1 gene encoding peroxisomal ABC transporter adrenoleukodystrophy protein (ALDP). Metabolic dysfunction in X-ALD is characterized by the accumulation of very long chain fatty acids (VLCFAs; ≥ C22:0) in the tissues and plasma of patients. Here, we investigated the mitochondrial status following deletion of ABCD1 in B12 oligodendrocytes and U87 astrocytes. This study provides evidence that silencing of peroxisomal protein ABCD1 produces structural and functional perturbations in mitochondria. Activities of electron transport chain-related enzymes and of citric acid cycle (TCA cycle) were reduced; mitochondrial redox status was dysregulated and the mitochondrial membrane potential was disrupted following ABCD1 silencing. A greater reduction of ATP levels and citrate synthase activities was observed in oligodendrocytes as compared to astrocytes. Further, most of the mitochondrial perturbations induced by ABCD1 silencing were corrected by treating cells with SAHA (suberoylanilide hydroxamic acid), an HDAC inhibitor. These observations indicate a novel relationship between peroxisomes and mitochondria in cellular homeostasis and the importance of intact peroxisomes in relation to mitochondrial integrity and function in the cell types that participate in the pathobiology of X-ALD. These observations suggest SAHA as a potential therapy for X-ALD. PMID:25393703

  16. Topoisomerase I inhibitor, camptothecin, induces apoptogenic signaling in human embryonic stem cells.

    PubMed

    García, Carolina Paola; Videla Richardson, Guillermo Agustín; Romorini, Leonardo; Miriuka, Santiago Gabriel; Sevlever, Gustavo Emilio; Scassa, María Elida

    2014-03-01

    Embryonic stem cells (ESCs) need to maintain their genomic integrity in response to DNA damage to safeguard the integrity of the organism. DNA double strand breaks (DSBs) are one of the most lethal forms of DNA damage and, if not repaired correctly, they can lead to cell death, genomic instability and cancer. How human ESCs (hESCs) maintain genomic integrity in response to agents that cause DSBs is relatively unclear. In the present study we aim to determine the hESC response to the DSB inducing agent camptothecin (CPT). We find that hESCs are hypersensitive to CPT, as evidenced by high levels of apoptosis. CPT treatment leads to DNA-damage sensor kinase (ATM and DNA-PKcs) phosphorylation on serine 1981 and serine 2056, respectively. Activation of ATM and DNA-PKcs was followed by histone H2AX phosphorylation on Ser 139, a sensitive reporter of DNA damage. Nuclear accumulation and ATM-dependent phosphorylation of p53 on serine 15 were also observed. Remarkably, hESC viability was further decreased when ATM or DNA-PKcs kinase activity was impaired by the use of specific inhibitors. The hypersensitivity to CPT treatment was markedly reduced by blocking p53 translocation to mitochondria with pifithrin-μ. Importantly, programmed cell death was achieved in the absence of the cyclin dependent kinase inhibitor, p21(Waf1), a bona fide p53 target gene. Conversely, differentiated hESCs were no longer highly sensitive to CPT. This attenuated apoptotic response was accompanied by changes in cell cycle profile and by the presence of p21(Waf1). The results presented here suggest that p53 has a key involvement in preventing the propagation of damaged hESCs when genome is threatened. As a whole, our findings support the concept that the phenomenon of apoptosis is a prominent player in normal embryonic development.

  17. Dietary Inulin Fibers Prevent Proton-Pump Inhibitor (PPI)-Induced Hypocalcemia in Mice

    PubMed Central

    Hess, Mark W.; de Baaij, Jeroen H. F.; Gommers, Lisanne M. M.; Hoenderop, Joost G. J.; Bindels, René J. M.

    2015-01-01

    Background Proton-pump inhibitor-induced hypomagnesemia (PPIH) is the most recognized side effect of proton-pump inhibitors (PPIs). Additionally, PPIH is associated with hypocalcemia and hypokalemia. It is hypothesized that PPIs reduce epithelial proton secretion and thereby increase the pH in the colon, which may explain the reduced absorption of and Mg2+ and Ca2+. Fermentation of dietary oligofructose-enriched inulin fibers by the microflora leads to acidification of the intestinal lumen and by this enhances mineral uptake. This study aimed, therefore, to improve mineral absorption by application of dietary inulin to counteract PPIH. Methods Here, C57BL/J6 mice were supplemented with omeprazole and/or inulin. Subsequently, Mg2+ and Ca2+ homeostasis was assessed by means of serum, urine and fecal electrolyte measurements. Moreover, the mRNA levels of magnesiotropic and calciotropic genes were examined in the large intestine and kidney by real-time PCR. Results Treatment with omeprazole significantly reduced serum Mg2+ and Ca2+ levels. However, concomitant addition of dietary inulin fibers normalized serum Ca2+ but not serum Mg2+ concentrations. Inulin abolished enhanced expression of Trpv6 and S100g in the colon by omeprazole. Additionally, intestinal and renal mRNA levels of the Trpm6 gene were reduced after inulin intake. Conclusions This study suggests that dietary inulin counteracts reduced intestinal Ca2+ absorption upon PPI treatment. In contrast, inulin did not increase intestinal absorption of Mg2+ sufficiently to recover serum Mg2+. The clinical potential of dietary inulin treatment should be the subject of future studies. PMID:26397986

  18. Peroxisomes Are Required for in Vivo Nitric Oxide Accumulation in the Cytosol following Salinity Stress of Arabidopsis Plants1[C][W][OA

    PubMed Central

    Corpas, Francisco J.; Hayashi, Makoto; Mano, Shoji; Nishimura, Mikio; Barroso, Juan B.

    2009-01-01

    Peroxisomes are unique organelles involved in multiple cellular metabolic pathways. Nitric oxide (NO) is a free radical active in many physiological functions under normal and stress conditions. Using Arabidopsis (Arabidopsis thaliana) wild type and mutants expressing green fluorescent protein through the addition of peroxisomal targeting signal 1 (PTS1), which enables peroxisomes to be visualized in vivo, this study analyzes the temporal and cell distribution of NO during the development of 3-, 5-, 8-, and 11-d-old Arabidopsis seedlings and shows that Arabidopsis peroxisomes accumulate NO in vivo. Pharmacological analyses using nitric oxide synthase (NOS) inhibitors detected the presence of putative calcium-dependent NOS activity. Furthermore, peroxins Pex12 and Pex13 appear to be involved in transporting the putative NOS protein to peroxisomes, since pex12 and pex13 mutants, which are defective in PTS1- and PTS2-dependent protein transport to peroxisomes, registered lower NO content. Additionally, we show that under salinity stress (100 mm NaCl), peroxisomes are required for NO accumulation in the cytosol, thereby participating in the generation of peroxynitrite (ONOO−) and in increasing protein tyrosine nitration, which is a marker of nitrosative stress. PMID:19783645

  19. Inhibitors of cyclooxygenase-2, but not cyclooxygenase-1 provide structural and functional protection against quinolinic acid-induced neurodegeneration.

    PubMed

    Salzberg-Brenhouse, Heather C; Chen, Er-Yun; Emerich, Dwaine F; Baldwin, Sam; Hogeland, Ken; Ranelli, Sharon; Lafreniere, Denise; Perdomo, Brigido; Novak, Leah; Kladis, Theodora; Fu, Karen; Basile, Anthony S; Kordower, Jeffrey H; Bartus, Raymond T

    2003-07-01

    Cyclooxygenases (COXs) are implicated in neurodegenerative processes associated with acute and chronic neurological diseases. Given the potential utility of COX inhibitors in treating these disorders, we examined the nonselective COX inhibitor flurbiprofen, the specific COX-1 inhibitor valeryl salicylate (VS), and the COX-2 inhibitor N-[2-(cyclohexyloxy)-4-nitrophenyl]methanesulfonamide (NS-398) for their abilities to protect striatal neurons against a quinolinic acid (QA)-induced excitotoxic lesion. Rats were administered COX inhibitors 10 min before a unilateral QA lesion of the striatum, and then tested 2 to 3 weeks later in a battery of motor tasks (bracing, placing, akinesia, and apomorphine-induced rotations). Lesion volume was assessed using immunohistochemical methods 1 month after lesioning. Orally administered flurbiprofen (50 mg) was highly neuroprotective, preserving 84 to 99% of motor performance (ED50 = 8.6-9.7 mg) while reducing lesion volume 75% (ED50 = 3.2 mg). The identities of the COX isoforms associated with QA-induced neurodegeneration were determined using VS and NS-398. Oral VS was ineffective in virtually all indices of functional neuroprotection. In contrast, oral NS-398 was highly effective, preserving approximately 83% of motor performance at2mg(ED50 = 0.1-0.4 mg), and reducing lesion volume 100% (ED50 = 0.4 mg). Similar results were obtained using inhaled flurbiprofen (2 mg), which preserved 88 to 100% of motor performance while reducing striatal lesion size 92%. These results demonstrate that COX-2 inhibition protects neurons from acute, excitotoxic neurodegeneration. Moreover, formulating a nonselective COX inhibitor into an inhalable preparation dramatically improves its potency in treating acute neuronal damage, a situation where the rapidity of drug delivery and onset of action is critical to clinical efficacy.

  20. Histone Deacetylase Inhibitor Trichostatin A Ameliorated Endotoxin-Induced Neuroinflammation and Cognitive Dysfunction

    PubMed Central

    Hsing, Chung-Hsi; Hung, Shih-Kai; Chen, Yeong-Chang; Wei, Tsui-Shan; Sun, Ding-Ping; Wang, Jhi-Joung; Yeh, Ching-Hua

    2015-01-01

    Excessive production of cytokines by microglia may cause cognitive dysfunction and long-lasting behavioral changes. Activating the peripheral innate immune system stimulates cytokine secretion in the central nervous system, which modulates cognitive function. Histone deacetylases (HDACs) modulate cytokine synthesis and release. Trichostatin A (TSA), an HDAC inhibitor, is documented to be anti-inflammatory and neuroprotective. We investigated whether TSA reduces lipopolysaccharide- (LPS-) induced neuroinflammation and cognitive dysfunction. ICR mice were first intraperitoneally (i.p.) injected with vehicle or TSA (0.3 mg/kg). One hour later, they were injected (i.p.) with saline or Escherichia coli LPS (1 mg/kg). We analyzed the food and water intake, body weight loss, and sucrose preference of the injected mice and then determined the microglia activation and inflammatory cytokine expression in the brains of LPS-treated mice and LPS-treated BV-2 microglial cells. In the TSA-pretreated mice, microglial activation was lower, anhedonia did not occur, and LPS-induced cognitive dysfunction (anorexia, weight loss, and social withdrawal) was attenuated. Moreover, mRNA expression of HDAC2, HDAC5, indoleamine 2,3-dioxygenase (IDO), TNF-α, MCP-1, and IL-1β in the brain of LPS-challenged mice and in the LPS-treated BV-2 microglial cells was lower. TSA diminished LPS-induced inflammatory responses in the mouse brain and modulated the cytokine-associated changes in cognitive function, which might be specifically related to reducing HDAC2 and HDAC5 expression. PMID:26273133

  1. Trichostatin A, a histone deacetylase inhibitor, modulates unloaded-induced skeletal muscle atrophy.

    PubMed

    Dupré-Aucouturier, Sylvie; Castells, Josiane; Freyssenet, Damien; Desplanches, Dominique

    2015-08-15

    Skeletal muscle atrophy is commonly associated with immobilization, ageing, and catabolic diseases such as diabetes and cancer cachexia. Epigenetic regulation of gene expression resulting from chromatin remodeling through histone acetylation has been implicated in muscle disuse. The present work was designed to test the hypothesis that treatment with trichostatin A (TSA), a histone deacetylase inhibitor, would partly counteract unloading-induced muscle atrophy. Soleus muscle atrophy (-38%) induced by 14 days of rat hindlimb suspension was reduced to only 25% under TSA treatment. TSA partly prevented the loss of type I and IIa fiber size and reversed the transitions of slow-twitch to fast-twitch fibers in soleus muscle. Unloading or TSA treatment did not affect myostatin gene expression and follistatin protein. Soleus protein carbonyl content remained unchanged, whereas the decrease in glutathione vs. glutathione disulfide ratio and the increase in catalase activity (biomarkers of oxidative stress) observed after unloading were abolished by TSA treatment. The autophagy-lysosome pathway (Bnip3 and microtubule-associated protein 1 light chain 3 proteins, Atg5, Gabarapl1, Ulk1, and cathepsin B and L mRNA) was not activated by unloading or TSA treatment. However, TSA suppressed the rise in muscle-specific RING finger protein 1 (MuRF1) caused by unloading without affecting the forkhead box (Foxo3) transcription factor. Prevention of muscle atrophy by TSA might be due to the regulation of the skeletal muscle atrophy-related MuRF1 gene. Our findings suggest that TSA may provide a novel avenue to treat unloaded-induced muscle atrophy. PMID:26112243

  2. Simotinib as a modulator of P-glycoprotein: substrate, inhibitor, or inducer?

    PubMed

    Huang, Lingling; Shen, Cheng; Chen, Yanfen; Yan, Huiwen; Cheng, Zeneng; Zhu, Qubo

    2016-04-01

    As a new antitumor drug, simotinib hydrochloride is prescribed for prolonged periods, often to patients with comorbidities. Therefore, the risk for developing drug resistance and drug-drug interactions between simotinib and other agents has to be taken into consideration. As P-glycoprotein (P-gp) is an efflux transporter, which plays a significant role in drug resistance and influences the pharmacological properties and toxicities of the drugs it interacts with, the interactions between simotinib and P-gp were investigated. Cytotoxicity was measured using the 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2H-tetrazolium bromide assay. Intracellular drug concentrations were detected by high-performance liquid chromatography, fluorescence-activated cell sorting and using a fluorescence reader. P-gp ATPase activity was measured using the Pgp-Glo assay, and intracellular pH was assessed using the fluorescent probe 2',7'-bis(2-carboxyethyl)-5(6)-carboxyfluorescein acetoxymethyl. The expression and transcription of P-gp were detected by western blotting and the luciferase assay. Simotinib has no cross-resistance to P-gp substrates, and its efflux rate was independent of either the P-gp expression or the coadministered P-gp substrate. Simotinib reversed chemotherapeutic agent resistance in a short time by increasing the intracellular concentration of the chemotherapeutic agent and blocked rhodamine 123 efflux. Further studies demonstrated that simotinib inhibited P-gp activity by modulating its ATPase activity and the intracellular pH. Although simotinib induced P-gp expression after extended treatment, the induced expression of P-gp had little impact on drug resistance. Simotinib is not a substrate of P-gp. As a modulator, it functions mainly as an inhibitor of P-gp by modulating the intracellular pH and ATPase activity, although it also induces P-gp expression after extended treatment.

  3. SLCO1B1 Variants and Angiotensin Converting Enzyme Inhibitor (Enalapril) -Induced Cough: a Pharmacogenetic Study

    PubMed Central

    Luo, Jian-Quan; He, Fa-Zhong; Wang, Zhen-Min; Sun, Ning-Ling; Wang, Lu-Yan; Tang, Gen-Fu; Liu, Mou-Ze; Li, Qing; Chen, Xiao-Ping; Liu, Zhao-Qian; Zhou, Hong-Hao; Zhang, Wei

    2015-01-01

    Clinical observations suggest that incidence of cough in Chinese taking angiotensin converting enzyme inhibitors is much higher than other racial groups. Cough is the most common adverse reaction of enalapril. We investigate whether SLCO1B1 genetic polymorphisms, previously reported to be important determinants of inter-individual variability in enalapril pharmacokinetics, are associated with the enalapril-induced cough. A cohort of 450 patients with essential hypertension taking 10 mg enalapril maleate were genotyped for the functional SLCO1B1 variants, 388A > G (Asn130Asp, rs2306283) and 521T > C (Val174Ala, rs4149056). The primary endpoint was cough, which was recorded when participants were bothered by cough and respiratory symptoms during enalapril treatment without an identifiable cause. SLCO1B1 521C allele conferred a 2-fold relative risk of enalapril-induced cough (95% confidence interval [CI] = 1.34–3.04, P = 6.2 × 10−4), and haplotype analysis suggested the relative risk of cough was 6.94-fold (95% CI = 1.30–37.07, P = 0.020) in SLCO1B1*15/*15 carriers. Furthermore, there was strong evidence for a gene-dose effect (percent with cough in those with 0, 1, or 2 copy of the 521C allele: 28.2%, 42.5%, and 71.4%, trend P = 6.6 × 10−4). Our study highlights, for the first time, SLCO1B1 variants are strongly associated with an increased risk of enalapril-induced cough. The findings will be useful to provide pharmacogenetic markers for enalapril treatment. PMID:26607661

  4. Simotinib as a modulator of P-glycoprotein: substrate, inhibitor, or inducer?

    PubMed

    Huang, Lingling; Shen, Cheng; Chen, Yanfen; Yan, Huiwen; Cheng, Zeneng; Zhu, Qubo

    2016-04-01

    As a new antitumor drug, simotinib hydrochloride is prescribed for prolonged periods, often to patients with comorbidities. Therefore, the risk for developing drug resistance and drug-drug interactions between simotinib and other agents has to be taken into consideration. As P-glycoprotein (P-gp) is an efflux transporter, which plays a significant role in drug resistance and influences the pharmacological properties and toxicities of the drugs it interacts with, the interactions between simotinib and P-gp were investigated. Cytotoxicity was measured using the 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2H-tetrazolium bromide assay. Intracellular drug concentrations were detected by high-performance liquid chromatography, fluorescence-activated cell sorting and using a fluorescence reader. P-gp ATPase activity was measured using the Pgp-Glo assay, and intracellular pH was assessed using the fluorescent probe 2',7'-bis(2-carboxyethyl)-5(6)-carboxyfluorescein acetoxymethyl. The expression and transcription of P-gp were detected by western blotting and the luciferase assay. Simotinib has no cross-resistance to P-gp substrates, and its efflux rate was independent of either the P-gp expression or the coadministered P-gp substrate. Simotinib reversed chemotherapeutic agent resistance in a short time by increasing the intracellular concentration of the chemotherapeutic agent and blocked rhodamine 123 efflux. Further studies demonstrated that simotinib inhibited P-gp activity by modulating its ATPase activity and the intracellular pH. Although simotinib induced P-gp expression after extended treatment, the induced expression of P-gp had little impact on drug resistance. Simotinib is not a substrate of P-gp. As a modulator, it functions mainly as an inhibitor of P-gp by modulating the intracellular pH and ATPase activity, although it also induces P-gp expression after extended treatment. PMID:26766493

  5. The Proteome of Human Liver Peroxisomes: Identification of Five New Peroxisomal Constituents by a Label-Free Quantitative Proteomics Survey

    PubMed Central

    Ofman, Rob; Bunse, Christian; Pawlas, Magdalena; Hayen, Heiko; Eisenacher, Martin; Stephan, Christian; Meyer, Helmut E.; Waterham, Hans R.; Erdmann, Ralf; Wanders, Ronald J.; Warscheid, Bettina

    2013-01-01

    The peroxisome is a key organelle of low abundance that fulfils various functions essential for human cell metabolism. Severe genetic diseases in humans are caused by defects in peroxisome biogenesis or deficiencies in the function of single peroxisomal proteins. To improve our knowledge of this important cellular structure, we studied for the first time human liver peroxisomes by quantitative proteomics. Peroxisomes were isolated by differential and Nycodenz density gradient centrifugation. A label-free quantitative study of 314 proteins across the density gradient was accomplished using high resolution mass spectrometry. By pairing statistical data evaluation, cDNA cloning and in vivo colocalization studies, we report the association of five new proteins with human liver peroxisomes. Among these, isochorismatase domain containing 1 protein points to the existence of a new metabolic pathway and hydroxysteroid dehydrogenase like 2 protein is likely involved in the transport or β-oxidation of fatty acids in human peroxisomes. The detection of alcohol dehydrogenase 1A suggests the presence of an alternative alcohol-oxidizing system in hepatic peroxisomes. In addition, lactate dehydrogenase A and malate dehydrogenase 1 partially associate with human liver peroxisomes and enzyme activity profiles support the idea that NAD+ becomes regenerated during fatty acid β-oxidation by alternative shuttling processes in human peroxisomes involving lactate dehydrogenase and/or malate dehydrogenase. Taken together, our data represent a valuable resource for future studies of peroxisome biochemistry that will advance research of human peroxisomes in health and disease. PMID:23460848

  6. Peroxisome dynamics during development of the fungus Podospora anserina.

    PubMed

    Takano-Rojas, Harumi; Zickler, Denise; Peraza-Reyes, Leonardo

    2016-01-01

    Peroxisomes are versatile and dynamic organelles that are required for the development of diverse eukaryotic organisms. We demonstrated previously that in the fungus Podospora anserina different peroxisomal functions are required at distinct stages of sexual development, including the initiation and progression of meiocyte (ascus) development and the differentiation and germination of sexual spores (ascospores). Peroxisome assembly during these processes relies on the differential activity of the protein machinery that drives the import of proteins into the organelle, indicating a complex developmental regulation of peroxisome formation and activity. Here we demonstrate that peroxisome dynamics is also highly regulated during development. We show that peroxisomes in P. anserina are highly dynamic and respond to metabolic and environmental cues by undergoing changes in size, morphology and number. In addition, peroxisomes of vegetative and sexual cell types are structurally different. During sexual development peroxisome number increases at two stages: at early ascus differentiation and during ascospore formation. These processes are accompanied by changes in peroxisome structure and distribution, which include a cell-polarized concentration of peroxisomes at the beginning of ascus development, as well as a morphological transition from predominantly spherical to elongated shapes at the end of the first meiotic division. Further, the mostly tubular peroxisomes present from second meiotic division to early ascospore formation again become rounded during ascospore differentiation. Ultimately the number of peroxisomes dramatically decreases upon ascospore maturation. Our results reveal a precise regulation of peroxisome dynamics during sexual development and suggest that peroxisome constitution and function during development is defined by the coordinated regulation of the proteins that control peroxisome assembly and dynamics.

  7. Sphingosine 1-phosphate is a ligand for peroxisome proliferator-activated receptor-γ that regulates neoangiogenesis.

    PubMed

    Parham, Kate A; Zebol, Julia R; Tooley, Katie L; Sun, Wai Y; Moldenhauer, Lachlan M; Cockshell, Michaelia P; Gliddon, Briony L; Moretti, Paul A; Tigyi, Gabor; Pitson, Stuart M; Bonder, Claudine S

    2015-09-01

    Sphingosine 1-phosphate (S1P) is a bioactive lipid that can function both extracellularly and intracellularly to mediate a variety of cellular processes. Using lipid affinity matrices and a radiolabeled lipid binding assay, we reveal that S1P directly interacts with the transcription factor peroxisome proliferator-activated receptor (PPAR)γ. Herein, we show that S1P treatment of human endothelial cells (ECs) activated a luciferase-tagged PPARγ-specific gene reporter by ∼12-fold, independent of the S1P receptors. More specifically, in silico docking, gene reporter, and binding assays revealed that His323 of the PPARγ ligand binding domain is important for binding to S1P. PPARγ functions when associated with coregulatory proteins, and herein we identify that peroxisome proliferator-activated receptor-γ coactivator 1 (PGC1)β binds to PPARγ in ECs and their progenitors (nonadherent endothelial forming cells) and that the formation of this PPARγ:PGC1β complex is increased in response to S1P. ECs treated with S1P selectively regulated known PPARγ target genes with PGC1β and plasminogen-activated inhibitor-1 being increased, no change to adipocyte fatty acid binding protein 2 and suppression of CD36. S1P-induced in vitro tube formation was significantly attenuated in the presence of the PPARγ antagonist GW9662, and in vivo application of GW9662 also reduced vascular development in Matrigel plugs. Interestingly, activation of PPARγ by the synthetic ligand troglitazone also reduced tube formation in vitro and in vivo. To support this, Sphk1(-/-)Sphk2(+/-) mice, with low circulating S1P levels, demonstrated a similar reduction in vascular development. Taken together, our data reveal that the transcription factor, PPARγ, is a bona fide intracellular target for S1P and thus suggest that the S1P:PPARγ:PGC1β complex may be a useful target to manipulate neovascularization.

  8. The novel HDAC inhibitor AR-42-induced anti-colon cancer cell activity is associated with ceramide production.

    PubMed

    Xu, Weihong; Xu, Bin; Yao, Yiting; Yu, Xiaoling; Shen, Jie

    2015-08-01

    In the current study, we investigated the potential activity of AR-42, a novel histone deacetylase (HDAC) inhibitor, against colon cancer cells. Our in vitro results showed that AR-42 induced ceramide production, exerted potent anti-proliferative and pro-apoptotic activities in established (SW-620 and HCT-116 lines) and primary human colon cancer cells. Exogenously-added sphingosine 1-phosphate (S1P) suppressed AR-42-induced activity, yet a cell-permeable ceramide (C4) facilitated AR-42-induced cytotoxicity against colon cancer cells. In addition, AR-42-induced ceramide production and anti-colon cancer cell activity were inhibited by the ceramide synthase inhibitor fumonisin B1, but were exacerbated by PDMP, which is a ceramide glucosylation inhibitor. In vivo, oral administration of a single dose of AR-42 dramatically inhibited SW-620 xenograft growth in severe combined immunodeficient (SCID) mice, without inducing overt toxicities. Together, these results show that AR-42 dramatically inhibits colon cancer cell proliferation in vitro and in vivo, and ceramide production might be the key mechanism responsible for its actions.

  9. Histone deacetylase inhibitors suppress RSV infection and alleviate virus-induced airway inflammation

    PubMed Central

    Feng, Qiuqin; Su, Zhonglan; Song, Shiyu; Xu, Hui; Zhang, Bin; Yi, Long; Tian, Man; Wang, Hongwei

    2016-01-01

    Respiratory syncytial virus (RSV) is the leading cause of lower respiratory tract infections in infants and young children. However, the majority of RSV-infected patients only show mild symptoms. Different severities of infection and responses among the RSV-infected population indicate that epigenetic regulation as well as personal genetic background may affect RSV infectivity. Histone deacetylase (HDAC) is an important epigenetic regulator in lung diseases. The present study aimed to explore the possible connection between HDAC expression and RSV-induced lung inflammation. To address this question, RSV-infected airway epithelial cells (BEAS-2B) were prepared and a mouse model of RSV infection was established, and then treated with various concentrations of HDAC inhibitors (HDACis), namely trichostatin A (TSA) and suberoylanilide hydroxamic acid (SAHA). Viral replication and markers of virus-induced airway inflammation or oxidative stress were assessed. The activation of the nuclear factor-κB (NF-κB), cyclo-oxygenase-2 (COX-2), mitogen-activated protein kinase (MAPK) and signal transducer and activator of transcription 3 (STAT3) signaling pathways was evaluated by western blot analysis. Our results showed that RSV infection in airway epithelial cells (AECs) significantly decreased histone acetylation levels by altering HDAC2 expression. The treatment of RSV-infected AECs with HDACis significantly restricted RSV replication by upregulating the interferon-α (IFN-α) related signaling pathways. The treatment of RSV-infected AECs with HDACis also significantly inhibited RSV-induced pro-inflammatory cytokine release [interleukin (IL)-6 and IL-8] and oxidative stress-related molecule production [malondialdehyde (MDA), and nitrogen monoxide (NO)]. The activation of NF-κB, COX-2, MAPK and Stat3, which orchestrate pro-inflammatory gene expression and oxidative stress injury, was also significantly inhibited. Our in vivo study using a mouse model of RSV infection

  10. Histone deacetylase inhibitors suppress RSV infection and alleviate virus-induced airway inflammation.

    PubMed

    Feng, Qiuqin; Su, Zhonglan; Song, Shiyu; Χu, Hui; Zhang, Bin; Yi, Long; Tian, Man; Wang, Hongwei

    2016-09-01

    Respiratory syncytial virus (RSV) is the leading cause of lower respiratory tract infections in infants and young children. However, the majority of RSV-infected patients only show mild symptoms. Different severities of infection and responses among the RSV-infected population indicate that epigenetic regulation as well as personal genetic background may affect RSV infectivity. Histone deacetylase (HDAC) is an important epigenetic regulator in lung diseases. The present study aimed to explore the possible connection between HDAC expression and RSV-induced lung inflammation. To address this question, RSV-infected airway epithelial cells (BEAS‑2B) were prepared and a mouse model of RSV infection was established, and then treated with various concentrations of HDAC inhibitors (HDACis), namely trichostatin A (TSA) and suberoylanilide hydroxamic acid (SAHA). Viral replication and markers of virus-induced airway inflammation or oxidative stress were assessed. The activation of the nuclear factor-κB (NF-κB), cyclo-oxygenase-2 (COX-2), mitogen-activated protein kinase (MAPK) and signal transducer and activator of transcription 3 (STAT3) signaling pathways was evaluated by western blot analysis. Our results showed that RSV infection in airway epithelial cells (AECs) significantly decreased histone acetylation levels by altering HDAC2 expression. The treatment of RSV-infected AECs with HDACis significantly restricted RSV replication by upregulating the interferon-α (IFN-α) related signaling pathways. The treatment of RSV-infected AECs with HDACis also significantly inhibited RSV-induced pro-inflammatory cytokine release [interleukin (IL)-6 and IL-8] and oxidative stress-related molecule production [malondialdehyde (MDA), and nitrogen monoxide (NO)]. The activation of NF-κB, COX-2, MAPK and Stat3, which orchestrate pro‑inflammatory gene expression and oxidative stress injury, was also significantly inhibited. Our in vivo study using a mouse model of

  11. Chemoprevention of azoxymethane-induced rat colon carcinogenesis by a xanthine oxidase inhibitor, 1'-acetoxychavicol acetate.

    PubMed

    Tanaka, T; Kawabata, K; Kakumoto, M; Makita, H; Matsunaga, K; Mori, H; Satoh, K; Hara, A; Murakami, A; Koshimizu, K; Ohigashi, H

    1997-09-01

    In our studies to find natural compounds with chemopreventive efficacy in foods, using azoxymethane (AOM)-induced colonic aberrant crypt foci and colonic mucosal cell proliferation as biomarkers, a xanthine oxidase inhibitor, 1'-acetoxychavicol acetate (ACA), present in the edible plant Languas galanga from Thailand was found to be effective. This study was conducted to test the ability of ACA to inhibit AOM-induced colon tumorigenesis when it was fed to rats during the initiation or post-initiation phase. Male F344 rats were given three weekly s.c. injections of AOM (15 mg/kg body weight) to induce colonic neoplasms. They were fed diet containing 100 or 500 ppm ACA for 4 weeks, starting one week before the first dosing of AOM (the initiation feeding). The other groups were fed the ACA diet for 34 weeks, starting one week after the last AOM injection (the post-initiation feeding). At the termination of the study (week 38), AOM had induced 71% incidence of colonic adenocarcinoma (12/17 rats). The initiation feeding with ACA caused significant reduction in the incidence of colon carcinoma (54% inhibition by 100 ppm ACA feeding and 77% inhibition by 500 ppm ACA feeding, P = 0.03 and P = 0.001, respectively). The post-initiation feeding with ACA also suppressed the incidence of colonic carcinoma (45% inhibition by 100 ppm ACA feeding and 93% inhibition by 500 ppm ACA feeding, P = 0.06 and P = 0.00003, respectively). Such inhibition was dose-dependent and was associated with suppression of pro